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3,164
Find the Number of Good Pairs II
Medium
<p>You are given 2 integer arrays <code>nums1</code> and <code>nums2</code> of lengths <code>n</code> and <code>m</code> respectively. You are also given a <strong>positive</strong> integer <code>k</code>.</p> <p>A pair <code>(i, j)</code> is called <strong>good</strong> if <code>nums1[i]</code> is divisible by <code>nums2[j] * k</code> (<code>0 &lt;= i &lt;= n - 1</code>, <code>0 &lt;= j &lt;= m - 1</code>).</p> <p>Return the total number of <strong>good</strong> pairs.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums1 = [1,3,4], nums2 = [1,3,4], k = 1</span></p> <p><strong>Output:</strong> <span class="example-io">5</span></p> <p><strong>Explanation:</strong></p> The 5 good pairs are <code>(0, 0)</code>, <code>(1, 0)</code>, <code>(1, 1)</code>, <code>(2, 0)</code>, and <code>(2, 2)</code>.</div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums1 = [1,2,4,12], nums2 = [2,4], k = 3</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The 2 good pairs are <code>(3, 0)</code> and <code>(3, 1)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n, m &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= nums1[i], nums2[j] &lt;= 10<sup>6</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>3</sup></code></li> </ul>
Array; Hash Table
Go
func numberOfPairs(nums1 []int, nums2 []int, k int) (ans int64) { cnt1 := map[int]int{} for _, x := range nums1 { if x%k == 0 { cnt1[x/k]++ } } if len(cnt1) == 0 { return 0 } cnt2 := map[int]int{} for _, x := range nums2 { cnt2[x]++ } mx := 0 for x := range cnt1 { mx = max(mx, x) } for x, v := range cnt2 { s := 0 for y := x; y <= mx; y += x { s += cnt1[y] } ans += int64(s) * int64(v) } return }
3,164
Find the Number of Good Pairs II
Medium
<p>You are given 2 integer arrays <code>nums1</code> and <code>nums2</code> of lengths <code>n</code> and <code>m</code> respectively. You are also given a <strong>positive</strong> integer <code>k</code>.</p> <p>A pair <code>(i, j)</code> is called <strong>good</strong> if <code>nums1[i]</code> is divisible by <code>nums2[j] * k</code> (<code>0 &lt;= i &lt;= n - 1</code>, <code>0 &lt;= j &lt;= m - 1</code>).</p> <p>Return the total number of <strong>good</strong> pairs.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums1 = [1,3,4], nums2 = [1,3,4], k = 1</span></p> <p><strong>Output:</strong> <span class="example-io">5</span></p> <p><strong>Explanation:</strong></p> The 5 good pairs are <code>(0, 0)</code>, <code>(1, 0)</code>, <code>(1, 1)</code>, <code>(2, 0)</code>, and <code>(2, 2)</code>.</div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums1 = [1,2,4,12], nums2 = [2,4], k = 3</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The 2 good pairs are <code>(3, 0)</code> and <code>(3, 1)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n, m &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= nums1[i], nums2[j] &lt;= 10<sup>6</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>3</sup></code></li> </ul>
Array; Hash Table
Java
class Solution { public long numberOfPairs(int[] nums1, int[] nums2, int k) { Map<Integer, Integer> cnt1 = new HashMap<>(); for (int x : nums1) { if (x % k == 0) { cnt1.merge(x / k, 1, Integer::sum); } } if (cnt1.isEmpty()) { return 0; } Map<Integer, Integer> cnt2 = new HashMap<>(); for (int x : nums2) { cnt2.merge(x, 1, Integer::sum); } long ans = 0; int mx = Collections.max(cnt1.keySet()); for (var e : cnt2.entrySet()) { int x = e.getKey(), v = e.getValue(); int s = 0; for (int y = x; y <= mx; y += x) { s += cnt1.getOrDefault(y, 0); } ans += 1L * s * v; } return ans; } }
3,164
Find the Number of Good Pairs II
Medium
<p>You are given 2 integer arrays <code>nums1</code> and <code>nums2</code> of lengths <code>n</code> and <code>m</code> respectively. You are also given a <strong>positive</strong> integer <code>k</code>.</p> <p>A pair <code>(i, j)</code> is called <strong>good</strong> if <code>nums1[i]</code> is divisible by <code>nums2[j] * k</code> (<code>0 &lt;= i &lt;= n - 1</code>, <code>0 &lt;= j &lt;= m - 1</code>).</p> <p>Return the total number of <strong>good</strong> pairs.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums1 = [1,3,4], nums2 = [1,3,4], k = 1</span></p> <p><strong>Output:</strong> <span class="example-io">5</span></p> <p><strong>Explanation:</strong></p> The 5 good pairs are <code>(0, 0)</code>, <code>(1, 0)</code>, <code>(1, 1)</code>, <code>(2, 0)</code>, and <code>(2, 2)</code>.</div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums1 = [1,2,4,12], nums2 = [2,4], k = 3</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The 2 good pairs are <code>(3, 0)</code> and <code>(3, 1)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n, m &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= nums1[i], nums2[j] &lt;= 10<sup>6</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>3</sup></code></li> </ul>
Array; Hash Table
Python
class Solution: def numberOfPairs(self, nums1: List[int], nums2: List[int], k: int) -> int: cnt1 = Counter(x // k for x in nums1 if x % k == 0) if not cnt1: return 0 cnt2 = Counter(nums2) ans = 0 mx = max(cnt1) for x, v in cnt2.items(): s = sum(cnt1[y] for y in range(x, mx + 1, x)) ans += s * v return ans
3,164
Find the Number of Good Pairs II
Medium
<p>You are given 2 integer arrays <code>nums1</code> and <code>nums2</code> of lengths <code>n</code> and <code>m</code> respectively. You are also given a <strong>positive</strong> integer <code>k</code>.</p> <p>A pair <code>(i, j)</code> is called <strong>good</strong> if <code>nums1[i]</code> is divisible by <code>nums2[j] * k</code> (<code>0 &lt;= i &lt;= n - 1</code>, <code>0 &lt;= j &lt;= m - 1</code>).</p> <p>Return the total number of <strong>good</strong> pairs.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums1 = [1,3,4], nums2 = [1,3,4], k = 1</span></p> <p><strong>Output:</strong> <span class="example-io">5</span></p> <p><strong>Explanation:</strong></p> The 5 good pairs are <code>(0, 0)</code>, <code>(1, 0)</code>, <code>(1, 1)</code>, <code>(2, 0)</code>, and <code>(2, 2)</code>.</div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums1 = [1,2,4,12], nums2 = [2,4], k = 3</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The 2 good pairs are <code>(3, 0)</code> and <code>(3, 1)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n, m &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= nums1[i], nums2[j] &lt;= 10<sup>6</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>3</sup></code></li> </ul>
Array; Hash Table
TypeScript
function numberOfPairs(nums1: number[], nums2: number[], k: number): number { const cnt1: Map<number, number> = new Map(); for (const x of nums1) { if (x % k === 0) { cnt1.set((x / k) | 0, (cnt1.get((x / k) | 0) || 0) + 1); } } if (cnt1.size === 0) { return 0; } const cnt2: Map<number, number> = new Map(); for (const x of nums2) { cnt2.set(x, (cnt2.get(x) || 0) + 1); } const mx = Math.max(...cnt1.keys()); let ans = 0; for (const [x, v] of cnt2) { let s = 0; for (let y = x; y <= mx; y += x) { s += cnt1.get(y) || 0; } ans += s * v; } return ans; }
3,165
Maximum Sum of Subsequence With Non-adjacent Elements
Hard
<p>You are given an array <code>nums</code> consisting of integers. You are also given a 2D array <code>queries</code>, where <code>queries[i] = [pos<sub>i</sub>, x<sub>i</sub>]</code>.</p> <p>For query <code>i</code>, we first set <code>nums[pos<sub>i</sub>]</code> equal to <code>x<sub>i</sub></code>, then we calculate the answer to query <code>i</code> which is the <strong>maximum</strong> sum of a <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code> where <strong>no two adjacent elements are selected</strong>.</p> <p>Return the <em>sum</em> of the answers to all queries.</p> <p>Since the final answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p>A <strong>subsequence</strong> is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [3,5,9], queries = [[1,-2],[0,-3]]</span></p> <p><strong>Output:</strong> <span class="example-io">21</span></p> <p><strong>Explanation:</strong><br /> After the 1<sup>st</sup> query, <code>nums = [3,-2,9]</code> and the maximum sum of a subsequence with non-adjacent elements is <code>3 + 9 = 12</code>.<br /> After the 2<sup>nd</sup> query, <code>nums = [-3,-2,9]</code> and the maximum sum of a subsequence with non-adjacent elements is 9.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [0,-1], queries = [[0,-5]]</span></p> <p><strong>Output:</strong> <span class="example-io">0</span></p> <p><strong>Explanation:</strong><br /> After the 1<sup>st</sup> query, <code>nums = [-5,-1]</code> and the maximum sum of a subsequence with non-adjacent elements is 0 (choosing an empty subsequence).</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>-10<sup>5</sup> &lt;= nums[i] &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= queries.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>queries[i] == [pos<sub>i</sub>, x<sub>i</sub>]</code></li> <li><code>0 &lt;= pos<sub>i</sub> &lt;= nums.length - 1</code></li> <li><code>-10<sup>5</sup> &lt;= x<sub>i</sub> &lt;= 10<sup>5</sup></code></li> </ul>
Segment Tree; Array; Divide and Conquer; Dynamic Programming
C++
class Node { public: int l, r; long long s00, s01, s10, s11; Node(int l, int r) : l(l) , r(r) , s00(0) , s01(0) , s10(0) , s11(0) {} }; class SegmentTree { public: vector<Node*> tr; SegmentTree(int n) : tr(n << 2) { build(1, 1, n); } void build(int u, int l, int r) { tr[u] = new Node(l, r); if (l == r) { return; } int mid = (l + r) >> 1; build(u << 1, l, mid); build(u << 1 | 1, mid + 1, r); } long long query(int u, int l, int r) { if (tr[u]->l >= l && tr[u]->r <= r) { return tr[u]->s11; } int mid = (tr[u]->l + tr[u]->r) >> 1; long long ans = 0; if (r <= mid) { ans = query(u << 1, l, r); } if (l > mid) { ans = max(ans, query(u << 1 | 1, l, r)); } return ans; } void pushup(int u) { Node* left = tr[u << 1]; Node* right = tr[u << 1 | 1]; tr[u]->s00 = max(left->s00 + right->s10, left->s01 + right->s00); tr[u]->s01 = max(left->s00 + right->s11, left->s01 + right->s01); tr[u]->s10 = max(left->s10 + right->s10, left->s11 + right->s00); tr[u]->s11 = max(left->s10 + right->s11, left->s11 + right->s01); } void modify(int u, int x, int v) { if (tr[u]->l == tr[u]->r) { tr[u]->s11 = max(0LL, (long long) v); return; } int mid = (tr[u]->l + tr[u]->r) >> 1; if (x <= mid) { modify(u << 1, x, v); } else { modify(u << 1 | 1, x, v); } pushup(u); } ~SegmentTree() { for (auto node : tr) { delete node; } } }; class Solution { public: int maximumSumSubsequence(vector<int>& nums, vector<vector<int>>& queries) { int n = nums.size(); SegmentTree tree(n); for (int i = 0; i < n; ++i) { tree.modify(1, i + 1, nums[i]); } long long ans = 0; const int mod = 1e9 + 7; for (const auto& q : queries) { tree.modify(1, q[0] + 1, q[1]); ans = (ans + tree.query(1, 1, n)) % mod; } return (int) ans; } };
3,165
Maximum Sum of Subsequence With Non-adjacent Elements
Hard
<p>You are given an array <code>nums</code> consisting of integers. You are also given a 2D array <code>queries</code>, where <code>queries[i] = [pos<sub>i</sub>, x<sub>i</sub>]</code>.</p> <p>For query <code>i</code>, we first set <code>nums[pos<sub>i</sub>]</code> equal to <code>x<sub>i</sub></code>, then we calculate the answer to query <code>i</code> which is the <strong>maximum</strong> sum of a <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code> where <strong>no two adjacent elements are selected</strong>.</p> <p>Return the <em>sum</em> of the answers to all queries.</p> <p>Since the final answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p>A <strong>subsequence</strong> is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [3,5,9], queries = [[1,-2],[0,-3]]</span></p> <p><strong>Output:</strong> <span class="example-io">21</span></p> <p><strong>Explanation:</strong><br /> After the 1<sup>st</sup> query, <code>nums = [3,-2,9]</code> and the maximum sum of a subsequence with non-adjacent elements is <code>3 + 9 = 12</code>.<br /> After the 2<sup>nd</sup> query, <code>nums = [-3,-2,9]</code> and the maximum sum of a subsequence with non-adjacent elements is 9.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [0,-1], queries = [[0,-5]]</span></p> <p><strong>Output:</strong> <span class="example-io">0</span></p> <p><strong>Explanation:</strong><br /> After the 1<sup>st</sup> query, <code>nums = [-5,-1]</code> and the maximum sum of a subsequence with non-adjacent elements is 0 (choosing an empty subsequence).</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>-10<sup>5</sup> &lt;= nums[i] &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= queries.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>queries[i] == [pos<sub>i</sub>, x<sub>i</sub>]</code></li> <li><code>0 &lt;= pos<sub>i</sub> &lt;= nums.length - 1</code></li> <li><code>-10<sup>5</sup> &lt;= x<sub>i</sub> &lt;= 10<sup>5</sup></code></li> </ul>
Segment Tree; Array; Divide and Conquer; Dynamic Programming
Go
type Node struct { l, r int s00, s01, s10, s11 int } func NewNode(l, r int) *Node { return &Node{l: l, r: r, s00: 0, s01: 0, s10: 0, s11: 0} } type SegmentTree struct { tr []*Node } func NewSegmentTree(n int) *SegmentTree { tr := make([]*Node, n*4) tree := &SegmentTree{tr: tr} tree.build(1, 1, n) return tree } func (st *SegmentTree) build(u, l, r int) { st.tr[u] = NewNode(l, r) if l == r { return } mid := (l + r) >> 1 st.build(u<<1, l, mid) st.build(u<<1|1, mid+1, r) } func (st *SegmentTree) query(u, l, r int) int { if st.tr[u].l >= l && st.tr[u].r <= r { return st.tr[u].s11 } mid := (st.tr[u].l + st.tr[u].r) >> 1 ans := 0 if r <= mid { ans = st.query(u<<1, l, r) } if l > mid { ans = max(ans, st.query(u<<1|1, l, r)) } return ans } func (st *SegmentTree) pushup(u int) { left := st.tr[u<<1] right := st.tr[u<<1|1] st.tr[u].s00 = max(left.s00+right.s10, left.s01+right.s00) st.tr[u].s01 = max(left.s00+right.s11, left.s01+right.s01) st.tr[u].s10 = max(left.s10+right.s10, left.s11+right.s00) st.tr[u].s11 = max(left.s10+right.s11, left.s11+right.s01) } func (st *SegmentTree) modify(u, x, v int) { if st.tr[u].l == st.tr[u].r { st.tr[u].s11 = max(0, v) return } mid := (st.tr[u].l + st.tr[u].r) >> 1 if x <= mid { st.modify(u<<1, x, v) } else { st.modify(u<<1|1, x, v) } st.pushup(u) } func maximumSumSubsequence(nums []int, queries [][]int) (ans int) { n := len(nums) tree := NewSegmentTree(n) for i, x := range nums { tree.modify(1, i+1, x) } const mod int = 1e9 + 7 for _, q := range queries { tree.modify(1, q[0]+1, q[1]) ans = (ans + tree.query(1, 1, n)) % mod } return }
3,165
Maximum Sum of Subsequence With Non-adjacent Elements
Hard
<p>You are given an array <code>nums</code> consisting of integers. You are also given a 2D array <code>queries</code>, where <code>queries[i] = [pos<sub>i</sub>, x<sub>i</sub>]</code>.</p> <p>For query <code>i</code>, we first set <code>nums[pos<sub>i</sub>]</code> equal to <code>x<sub>i</sub></code>, then we calculate the answer to query <code>i</code> which is the <strong>maximum</strong> sum of a <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code> where <strong>no two adjacent elements are selected</strong>.</p> <p>Return the <em>sum</em> of the answers to all queries.</p> <p>Since the final answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p>A <strong>subsequence</strong> is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [3,5,9], queries = [[1,-2],[0,-3]]</span></p> <p><strong>Output:</strong> <span class="example-io">21</span></p> <p><strong>Explanation:</strong><br /> After the 1<sup>st</sup> query, <code>nums = [3,-2,9]</code> and the maximum sum of a subsequence with non-adjacent elements is <code>3 + 9 = 12</code>.<br /> After the 2<sup>nd</sup> query, <code>nums = [-3,-2,9]</code> and the maximum sum of a subsequence with non-adjacent elements is 9.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [0,-1], queries = [[0,-5]]</span></p> <p><strong>Output:</strong> <span class="example-io">0</span></p> <p><strong>Explanation:</strong><br /> After the 1<sup>st</sup> query, <code>nums = [-5,-1]</code> and the maximum sum of a subsequence with non-adjacent elements is 0 (choosing an empty subsequence).</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>-10<sup>5</sup> &lt;= nums[i] &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= queries.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>queries[i] == [pos<sub>i</sub>, x<sub>i</sub>]</code></li> <li><code>0 &lt;= pos<sub>i</sub> &lt;= nums.length - 1</code></li> <li><code>-10<sup>5</sup> &lt;= x<sub>i</sub> &lt;= 10<sup>5</sup></code></li> </ul>
Segment Tree; Array; Divide and Conquer; Dynamic Programming
Java
class Node { int l, r; long s00, s01, s10, s11; Node(int l, int r) { this.l = l; this.r = r; this.s00 = this.s01 = this.s10 = this.s11 = 0; } } class SegmentTree { Node[] tr; SegmentTree(int n) { tr = new Node[n * 4]; build(1, 1, n); } void build(int u, int l, int r) { tr[u] = new Node(l, r); if (l == r) { return; } int mid = (l + r) >> 1; build(u << 1, l, mid); build(u << 1 | 1, mid + 1, r); } long query(int u, int l, int r) { if (tr[u].l >= l && tr[u].r <= r) { return tr[u].s11; } int mid = (tr[u].l + tr[u].r) >> 1; long ans = 0; if (r <= mid) { ans = query(u << 1, l, r); } if (l > mid) { ans = Math.max(ans, query(u << 1 | 1, l, r)); } return ans; } void pushup(int u) { Node left = tr[u << 1]; Node right = tr[u << 1 | 1]; tr[u].s00 = Math.max(left.s00 + right.s10, left.s01 + right.s00); tr[u].s01 = Math.max(left.s00 + right.s11, left.s01 + right.s01); tr[u].s10 = Math.max(left.s10 + right.s10, left.s11 + right.s00); tr[u].s11 = Math.max(left.s10 + right.s11, left.s11 + right.s01); } void modify(int u, int x, int v) { if (tr[u].l == tr[u].r) { tr[u].s11 = Math.max(0, v); return; } int mid = (tr[u].l + tr[u].r) >> 1; if (x <= mid) { modify(u << 1, x, v); } else { modify(u << 1 | 1, x, v); } pushup(u); } } class Solution { public int maximumSumSubsequence(int[] nums, int[][] queries) { int n = nums.length; SegmentTree tree = new SegmentTree(n); for (int i = 0; i < n; ++i) { tree.modify(1, i + 1, nums[i]); } long ans = 0; final int mod = (int) 1e9 + 7; for (int[] q : queries) { tree.modify(1, q[0] + 1, q[1]); ans = (ans + tree.query(1, 1, n)) % mod; } return (int) ans; } }
3,165
Maximum Sum of Subsequence With Non-adjacent Elements
Hard
<p>You are given an array <code>nums</code> consisting of integers. You are also given a 2D array <code>queries</code>, where <code>queries[i] = [pos<sub>i</sub>, x<sub>i</sub>]</code>.</p> <p>For query <code>i</code>, we first set <code>nums[pos<sub>i</sub>]</code> equal to <code>x<sub>i</sub></code>, then we calculate the answer to query <code>i</code> which is the <strong>maximum</strong> sum of a <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code> where <strong>no two adjacent elements are selected</strong>.</p> <p>Return the <em>sum</em> of the answers to all queries.</p> <p>Since the final answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p>A <strong>subsequence</strong> is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [3,5,9], queries = [[1,-2],[0,-3]]</span></p> <p><strong>Output:</strong> <span class="example-io">21</span></p> <p><strong>Explanation:</strong><br /> After the 1<sup>st</sup> query, <code>nums = [3,-2,9]</code> and the maximum sum of a subsequence with non-adjacent elements is <code>3 + 9 = 12</code>.<br /> After the 2<sup>nd</sup> query, <code>nums = [-3,-2,9]</code> and the maximum sum of a subsequence with non-adjacent elements is 9.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [0,-1], queries = [[0,-5]]</span></p> <p><strong>Output:</strong> <span class="example-io">0</span></p> <p><strong>Explanation:</strong><br /> After the 1<sup>st</sup> query, <code>nums = [-5,-1]</code> and the maximum sum of a subsequence with non-adjacent elements is 0 (choosing an empty subsequence).</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>-10<sup>5</sup> &lt;= nums[i] &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= queries.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>queries[i] == [pos<sub>i</sub>, x<sub>i</sub>]</code></li> <li><code>0 &lt;= pos<sub>i</sub> &lt;= nums.length - 1</code></li> <li><code>-10<sup>5</sup> &lt;= x<sub>i</sub> &lt;= 10<sup>5</sup></code></li> </ul>
Segment Tree; Array; Divide and Conquer; Dynamic Programming
Python
def max(a: int, b: int) -> int: return a if a > b else b class Node: __slots__ = "l", "r", "s00", "s01", "s10", "s11" def __init__(self, l: int, r: int): self.l = l self.r = r self.s00 = self.s01 = self.s10 = self.s11 = 0 class SegmentTree: __slots__ = "tr" def __init__(self, n: int): self.tr: List[Node | None] = [None] * (n << 2) self.build(1, 1, n) def build(self, u: int, l: int, r: int): self.tr[u] = Node(l, r) if l == r: return mid = (l + r) >> 1 self.build(u << 1, l, mid) self.build(u << 1 | 1, mid + 1, r) def query(self, u: int, l: int, r: int) -> int: if self.tr[u].l >= l and self.tr[u].r <= r: return self.tr[u].s11 mid = (self.tr[u].l + self.tr[u].r) >> 1 ans = 0 if r <= mid: ans = self.query(u << 1, l, r) if l > mid: ans = max(ans, self.query(u << 1 | 1, l, r)) return ans def pushup(self, u: int): left, right = self.tr[u << 1], self.tr[u << 1 | 1] self.tr[u].s00 = max(left.s00 + right.s10, left.s01 + right.s00) self.tr[u].s01 = max(left.s00 + right.s11, left.s01 + right.s01) self.tr[u].s10 = max(left.s10 + right.s10, left.s11 + right.s00) self.tr[u].s11 = max(left.s10 + right.s11, left.s11 + right.s01) def modify(self, u: int, x: int, v: int): if self.tr[u].l == self.tr[u].r: self.tr[u].s11 = max(0, v) return mid = (self.tr[u].l + self.tr[u].r) >> 1 if x <= mid: self.modify(u << 1, x, v) else: self.modify(u << 1 | 1, x, v) self.pushup(u) class Solution: def maximumSumSubsequence(self, nums: List[int], queries: List[List[int]]) -> int: n = len(nums) tree = SegmentTree(n) for i, x in enumerate(nums, 1): tree.modify(1, i, x) ans = 0 mod = 10**9 + 7 for i, x in queries: tree.modify(1, i + 1, x) ans = (ans + tree.query(1, 1, n)) % mod return ans
3,165
Maximum Sum of Subsequence With Non-adjacent Elements
Hard
<p>You are given an array <code>nums</code> consisting of integers. You are also given a 2D array <code>queries</code>, where <code>queries[i] = [pos<sub>i</sub>, x<sub>i</sub>]</code>.</p> <p>For query <code>i</code>, we first set <code>nums[pos<sub>i</sub>]</code> equal to <code>x<sub>i</sub></code>, then we calculate the answer to query <code>i</code> which is the <strong>maximum</strong> sum of a <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code> where <strong>no two adjacent elements are selected</strong>.</p> <p>Return the <em>sum</em> of the answers to all queries.</p> <p>Since the final answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p>A <strong>subsequence</strong> is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [3,5,9], queries = [[1,-2],[0,-3]]</span></p> <p><strong>Output:</strong> <span class="example-io">21</span></p> <p><strong>Explanation:</strong><br /> After the 1<sup>st</sup> query, <code>nums = [3,-2,9]</code> and the maximum sum of a subsequence with non-adjacent elements is <code>3 + 9 = 12</code>.<br /> After the 2<sup>nd</sup> query, <code>nums = [-3,-2,9]</code> and the maximum sum of a subsequence with non-adjacent elements is 9.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [0,-1], queries = [[0,-5]]</span></p> <p><strong>Output:</strong> <span class="example-io">0</span></p> <p><strong>Explanation:</strong><br /> After the 1<sup>st</sup> query, <code>nums = [-5,-1]</code> and the maximum sum of a subsequence with non-adjacent elements is 0 (choosing an empty subsequence).</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>-10<sup>5</sup> &lt;= nums[i] &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= queries.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>queries[i] == [pos<sub>i</sub>, x<sub>i</sub>]</code></li> <li><code>0 &lt;= pos<sub>i</sub> &lt;= nums.length - 1</code></li> <li><code>-10<sup>5</sup> &lt;= x<sub>i</sub> &lt;= 10<sup>5</sup></code></li> </ul>
Segment Tree; Array; Divide and Conquer; Dynamic Programming
TypeScript
class Node { s00 = 0; s01 = 0; s10 = 0; s11 = 0; constructor( public l: number, public r: number, ) {} } class SegmentTree { tr: Node[]; constructor(n: number) { this.tr = Array(n * 4); this.build(1, 1, n); } build(u: number, l: number, r: number) { this.tr[u] = new Node(l, r); if (l === r) { return; } const mid = (l + r) >> 1; this.build(u << 1, l, mid); this.build((u << 1) | 1, mid + 1, r); } query(u: number, l: number, r: number): number { if (this.tr[u].l >= l && this.tr[u].r <= r) { return this.tr[u].s11; } const mid = (this.tr[u].l + this.tr[u].r) >> 1; let ans = 0; if (r <= mid) { ans = this.query(u << 1, l, r); } if (l > mid) { ans = Math.max(ans, this.query((u << 1) | 1, l, r)); } return ans; } pushup(u: number) { const left = this.tr[u << 1]; const right = this.tr[(u << 1) | 1]; this.tr[u].s00 = Math.max(left.s00 + right.s10, left.s01 + right.s00); this.tr[u].s01 = Math.max(left.s00 + right.s11, left.s01 + right.s01); this.tr[u].s10 = Math.max(left.s10 + right.s10, left.s11 + right.s00); this.tr[u].s11 = Math.max(left.s10 + right.s11, left.s11 + right.s01); } modify(u: number, x: number, v: number) { if (this.tr[u].l === this.tr[u].r) { this.tr[u].s11 = Math.max(0, v); return; } const mid = (this.tr[u].l + this.tr[u].r) >> 1; if (x <= mid) { this.modify(u << 1, x, v); } else { this.modify((u << 1) | 1, x, v); } this.pushup(u); } } function maximumSumSubsequence(nums: number[], queries: number[][]): number { const n = nums.length; const tree = new SegmentTree(n); for (let i = 0; i < n; i++) { tree.modify(1, i + 1, nums[i]); } let ans = 0; const mod = 1e9 + 7; for (const [i, x] of queries) { tree.modify(1, i + 1, x); ans = (ans + tree.query(1, 1, n)) % mod; } return ans; }
3,166
Calculate Parking Fees and Duration
Medium
<p>Table: <code>ParkingTransactions</code></p> <pre> +--------------+-----------+ | Column Name | Type | +--------------+-----------+ | lot_id | int | | car_id | int | | entry_time | datetime | | exit_time | datetime | | fee_paid | decimal | +--------------+-----------+ (lot_id, car_id, entry_time) is the primary key (combination of columns with unique values) for this table. Each row of this table contains the ID of the parking lot, the ID of the car, the entry and exit times, and the fee paid for the parking duration. </pre> <p>Write a solution to find the <strong>total parking fee</strong> paid by each car <strong>across all parking lots</strong>, and the <strong>average hourly fee</strong> (rounded to <code>2</code> decimal places) paid by <strong>each</strong> car. Also, find the <strong>parking lot</strong> where each car spent the <strong>most total time</strong>.</p> <p>Return <em>the result table ordered by </em><code>car_id</code><em><b> </b>in<b> ascending </b></em><em> order.</em></p> <p><strong>Note:</strong> Test cases are generated in such a way that an individual car cannot be in multiple parking lots at the same time.</p> <p>The result format is in the following example.</p> <p>&nbsp;</p> <p><strong class="example">Example:</strong></p> <div class="example-block"> <p><strong>Input:</strong></p> <p>ParkingTransactions table:</p> <pre class="example-io"> +--------+--------+---------------------+---------------------+----------+ | lot_id | car_id | entry_time | exit_time | fee_paid | +--------+--------+---------------------+---------------------+----------+ | 1 | 1001 | 2023-06-01 08:00:00 | 2023-06-01 10:30:00 | 5.00 | | 1 | 1001 | 2023-06-02 11:00:00 | 2023-06-02 12:45:00 | 3.00 | | 2 | 1001 | 2023-06-01 10:45:00 | 2023-06-01 12:00:00 | 6.00 | | 2 | 1002 | 2023-06-01 09:00:00 | 2023-06-01 11:30:00 | 4.00 | | 3 | 1001 | 2023-06-03 07:00:00 | 2023-06-03 09:00:00 | 4.00 | | 3 | 1002 | 2023-06-02 12:00:00 | 2023-06-02 14:00:00 | 2.00 | +--------+--------+---------------------+---------------------+----------+ </pre> <p><strong>Output:</strong></p> <pre class="example-io"> +--------+----------------+----------------+---------------+ | car_id | total_fee_paid | avg_hourly_fee | most_time_lot | +--------+----------------+----------------+---------------+ | 1001 | 18.00 | 2.40 | 1 | | 1002 | 6.00 | 1.33 | 2 | +--------+----------------+----------------+---------------+ </pre> <p><strong>Explanation:</strong></p> <ul> <li>For car ID 1001: <ul> <li>From 2023-06-01 08:00:00 to 2023-06-01 10:30:00 in lot 1: 2.5 hours, fee 5.00</li> <li>From 2023-06-02 11:00:00 to 2023-06-02 12:45:00 in lot 1: 1.75 hours, fee 3.00</li> <li>From 2023-06-01 10:45:00 to 2023-06-01 12:00:00 in lot 2: 1.25 hours, fee 6.00</li> <li>From 2023-06-03 07:00:00 to 2023-06-03 09:00:00 in lot 3: 2 hours, fee 4.00</li> </ul> Total fee paid: 18.00, total hours: 7.5, average hourly fee: 2.40, most time spent in lot 1: 4.25 hours.</li> <li>For car ID 1002: <ul> <li>From 2023-06-01 09:00:00 to 2023-06-01 11:30:00 in lot 2: 2.5 hours, fee 4.00</li> <li>From 2023-06-02 12:00:00 to 2023-06-02 14:00:00 in lot 3: 2 hours, fee 2.00</li> </ul> Total fee paid: 6.00, total hours: 4.5, average hourly fee: 1.33, most time spent in lot 2: 2.5 hours.</li> </ul> <p><b>Note:</b> Output table is ordered by car_id in ascending order.</p> </div>
Database
SQL
# Write your MySQL query statement below WITH T AS ( SELECT car_id, lot_id, SUM(TIMESTAMPDIFF(SECOND, entry_time, exit_time)) AS duration FROM ParkingTransactions GROUP BY 1, 2 ), P AS ( SELECT *, RANK() OVER ( PARTITION BY car_id ORDER BY duration DESC ) AS rk FROM T ) SELECT t1.car_id, SUM(fee_paid) AS total_fee_paid, ROUND( SUM(fee_paid) / (SUM(TIMESTAMPDIFF(SECOND, entry_time, exit_time)) / 3600), 2 ) AS avg_hourly_fee, t2.lot_id AS most_time_lot FROM ParkingTransactions AS t1 LEFT JOIN P AS t2 ON t1.car_id = t2.car_id AND t2.rk = 1 GROUP BY 1 ORDER BY 1;
3,167
Better Compression of String
Medium
<p>You are given a string <code>compressed</code> representing a compressed version of a string. The format is a character followed by its frequency. For example, <code>&quot;a3b1a1c2&quot;</code> is a compressed version of the string <code>&quot;aaabacc&quot;</code>.</p> <p>We seek a <strong>better compression</strong> with the following conditions:</p> <ol> <li>Each character should appear <strong>only once</strong> in the compressed version.</li> <li>The characters should be in <strong>alphabetical order</strong>.</li> </ol> <p>Return the <em>better compression</em> of <code>compressed</code>.</p> <p><strong>Note:</strong> In the better version of compression, the order of letters may change, which is acceptable.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;a3c9b2c1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a3b2c10&quot;</span></p> <p><strong>Explanation:</strong></p> <p>Characters &quot;a&quot; and &quot;b&quot; appear only once in the input, but &quot;c&quot; appears twice, once with a size of 9 and once with a size of 1.</p> <p>Hence, in the resulting string, it should have a size of 10.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;c2b3a1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a1b3c2&quot;</span></p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;a2b4c1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a2b4c1&quot;</span></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= compressed.length &lt;= 6 * 10<sup>4</sup></code></li> <li><code>compressed</code> consists only of lowercase English letters and digits.</li> <li><code>compressed</code> is a valid compression, i.e., each character is followed by its frequency.</li> <li>Frequencies are in the range <code>[1, 10<sup>4</sup>]</code> and have no leading zeroes.</li> </ul>
Hash Table; String; Counting; Sorting
C++
class Solution { public: string betterCompression(string compressed) { map<char, int> cnt; int i = 0; int n = compressed.length(); while (i < n) { char c = compressed[i]; int j = i + 1; int x = 0; while (j < n && isdigit(compressed[j])) { x = x * 10 + (compressed[j] - '0'); j++; } cnt[c] += x; i = j; } stringstream ans; for (const auto& entry : cnt) { ans << entry.first << entry.second; } return ans.str(); } };
3,167
Better Compression of String
Medium
<p>You are given a string <code>compressed</code> representing a compressed version of a string. The format is a character followed by its frequency. For example, <code>&quot;a3b1a1c2&quot;</code> is a compressed version of the string <code>&quot;aaabacc&quot;</code>.</p> <p>We seek a <strong>better compression</strong> with the following conditions:</p> <ol> <li>Each character should appear <strong>only once</strong> in the compressed version.</li> <li>The characters should be in <strong>alphabetical order</strong>.</li> </ol> <p>Return the <em>better compression</em> of <code>compressed</code>.</p> <p><strong>Note:</strong> In the better version of compression, the order of letters may change, which is acceptable.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;a3c9b2c1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a3b2c10&quot;</span></p> <p><strong>Explanation:</strong></p> <p>Characters &quot;a&quot; and &quot;b&quot; appear only once in the input, but &quot;c&quot; appears twice, once with a size of 9 and once with a size of 1.</p> <p>Hence, in the resulting string, it should have a size of 10.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;c2b3a1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a1b3c2&quot;</span></p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;a2b4c1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a2b4c1&quot;</span></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= compressed.length &lt;= 6 * 10<sup>4</sup></code></li> <li><code>compressed</code> consists only of lowercase English letters and digits.</li> <li><code>compressed</code> is a valid compression, i.e., each character is followed by its frequency.</li> <li>Frequencies are in the range <code>[1, 10<sup>4</sup>]</code> and have no leading zeroes.</li> </ul>
Hash Table; String; Counting; Sorting
Go
func betterCompression(compressed string) string { cnt := map[byte]int{} n := len(compressed) for i := 0; i < n; { c := compressed[i] j := i + 1 x := 0 for j < n && compressed[j] >= '0' && compressed[j] <= '9' { x = x*10 + int(compressed[j]-'0') j++ } cnt[c] += x i = j } ans := strings.Builder{} for c := byte('a'); c <= byte('z'); c++ { if cnt[c] > 0 { ans.WriteByte(c) ans.WriteString(strconv.Itoa(cnt[c])) } } return ans.String() }
3,167
Better Compression of String
Medium
<p>You are given a string <code>compressed</code> representing a compressed version of a string. The format is a character followed by its frequency. For example, <code>&quot;a3b1a1c2&quot;</code> is a compressed version of the string <code>&quot;aaabacc&quot;</code>.</p> <p>We seek a <strong>better compression</strong> with the following conditions:</p> <ol> <li>Each character should appear <strong>only once</strong> in the compressed version.</li> <li>The characters should be in <strong>alphabetical order</strong>.</li> </ol> <p>Return the <em>better compression</em> of <code>compressed</code>.</p> <p><strong>Note:</strong> In the better version of compression, the order of letters may change, which is acceptable.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;a3c9b2c1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a3b2c10&quot;</span></p> <p><strong>Explanation:</strong></p> <p>Characters &quot;a&quot; and &quot;b&quot; appear only once in the input, but &quot;c&quot; appears twice, once with a size of 9 and once with a size of 1.</p> <p>Hence, in the resulting string, it should have a size of 10.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;c2b3a1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a1b3c2&quot;</span></p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;a2b4c1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a2b4c1&quot;</span></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= compressed.length &lt;= 6 * 10<sup>4</sup></code></li> <li><code>compressed</code> consists only of lowercase English letters and digits.</li> <li><code>compressed</code> is a valid compression, i.e., each character is followed by its frequency.</li> <li>Frequencies are in the range <code>[1, 10<sup>4</sup>]</code> and have no leading zeroes.</li> </ul>
Hash Table; String; Counting; Sorting
Java
class Solution { public String betterCompression(String compressed) { Map<Character, Integer> cnt = new TreeMap<>(); int i = 0; int n = compressed.length(); while (i < n) { char c = compressed.charAt(i); int j = i + 1; int x = 0; while (j < n && Character.isDigit(compressed.charAt(j))) { x = x * 10 + (compressed.charAt(j) - '0'); j++; } cnt.merge(c, x, Integer::sum); i = j; } StringBuilder ans = new StringBuilder(); for (var e : cnt.entrySet()) { ans.append(e.getKey()).append(e.getValue()); } return ans.toString(); } }
3,167
Better Compression of String
Medium
<p>You are given a string <code>compressed</code> representing a compressed version of a string. The format is a character followed by its frequency. For example, <code>&quot;a3b1a1c2&quot;</code> is a compressed version of the string <code>&quot;aaabacc&quot;</code>.</p> <p>We seek a <strong>better compression</strong> with the following conditions:</p> <ol> <li>Each character should appear <strong>only once</strong> in the compressed version.</li> <li>The characters should be in <strong>alphabetical order</strong>.</li> </ol> <p>Return the <em>better compression</em> of <code>compressed</code>.</p> <p><strong>Note:</strong> In the better version of compression, the order of letters may change, which is acceptable.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;a3c9b2c1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a3b2c10&quot;</span></p> <p><strong>Explanation:</strong></p> <p>Characters &quot;a&quot; and &quot;b&quot; appear only once in the input, but &quot;c&quot; appears twice, once with a size of 9 and once with a size of 1.</p> <p>Hence, in the resulting string, it should have a size of 10.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;c2b3a1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a1b3c2&quot;</span></p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;a2b4c1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a2b4c1&quot;</span></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= compressed.length &lt;= 6 * 10<sup>4</sup></code></li> <li><code>compressed</code> consists only of lowercase English letters and digits.</li> <li><code>compressed</code> is a valid compression, i.e., each character is followed by its frequency.</li> <li>Frequencies are in the range <code>[1, 10<sup>4</sup>]</code> and have no leading zeroes.</li> </ul>
Hash Table; String; Counting; Sorting
Python
class Solution: def betterCompression(self, compressed: str) -> str: cnt = Counter() i, n = 0, len(compressed) while i < n: j = i + 1 x = 0 while j < n and compressed[j].isdigit(): x = x * 10 + int(compressed[j]) j += 1 cnt[compressed[i]] += x i = j return "".join(sorted(f"{k}{v}" for k, v in cnt.items()))
3,167
Better Compression of String
Medium
<p>You are given a string <code>compressed</code> representing a compressed version of a string. The format is a character followed by its frequency. For example, <code>&quot;a3b1a1c2&quot;</code> is a compressed version of the string <code>&quot;aaabacc&quot;</code>.</p> <p>We seek a <strong>better compression</strong> with the following conditions:</p> <ol> <li>Each character should appear <strong>only once</strong> in the compressed version.</li> <li>The characters should be in <strong>alphabetical order</strong>.</li> </ol> <p>Return the <em>better compression</em> of <code>compressed</code>.</p> <p><strong>Note:</strong> In the better version of compression, the order of letters may change, which is acceptable.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;a3c9b2c1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a3b2c10&quot;</span></p> <p><strong>Explanation:</strong></p> <p>Characters &quot;a&quot; and &quot;b&quot; appear only once in the input, but &quot;c&quot; appears twice, once with a size of 9 and once with a size of 1.</p> <p>Hence, in the resulting string, it should have a size of 10.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;c2b3a1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a1b3c2&quot;</span></p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">compressed = &quot;a2b4c1&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;a2b4c1&quot;</span></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= compressed.length &lt;= 6 * 10<sup>4</sup></code></li> <li><code>compressed</code> consists only of lowercase English letters and digits.</li> <li><code>compressed</code> is a valid compression, i.e., each character is followed by its frequency.</li> <li>Frequencies are in the range <code>[1, 10<sup>4</sup>]</code> and have no leading zeroes.</li> </ul>
Hash Table; String; Counting; Sorting
TypeScript
function betterCompression(compressed: string): string { const cnt = new Map<string, number>(); const n = compressed.length; let i = 0; while (i < n) { const c = compressed[i]; let j = i + 1; let x = 0; while (j < n && /\d/.test(compressed[j])) { x = x * 10 + +compressed[j]; j++; } cnt.set(c, (cnt.get(c) || 0) + x); i = j; } const keys = Array.from(cnt.keys()).sort(); const ans: string[] = []; for (const k of keys) { ans.push(`${k}${cnt.get(k)}`); } return ans.join(''); }
3,168
Minimum Number of Chairs in a Waiting Room
Easy
<p>You are given a string <code>s</code>. Simulate events at each second <code>i</code>:</p> <ul> <li>If <code>s[i] == &#39;E&#39;</code>, a person enters the waiting room and takes one of the chairs in it.</li> <li>If <code>s[i] == &#39;L&#39;</code>, a person leaves the waiting room, freeing up a chair.</li> </ul> <p>Return the <strong>minimum </strong>number of chairs needed so that a chair is available for every person who enters the waiting room given that it is initially <strong>empty</strong>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;EEEEEEE&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">7</span></p> <p><strong>Explanation:</strong></p> <p>After each second, a person enters the waiting room and no person leaves it. Therefore, a minimum of 7 chairs is needed.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;ELELEEL&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>Let&#39;s consider that there are 2 chairs in the waiting room. The table below shows the state of the waiting room at each second.</p> </div> <table> <tbody> <tr> <th>Second</th> <th>Event</th> <th>People in the Waiting Room</th> <th>Available Chairs</th> </tr> <tr> <td>0</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>1</td> <td>Leave</td> <td>0</td> <td>2</td> </tr> <tr> <td>2</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>3</td> <td>Leave</td> <td>0</td> <td>2</td> </tr> <tr> <td>4</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>5</td> <td>Enter</td> <td>2</td> <td>0</td> </tr> <tr> <td>6</td> <td>Leave</td> <td>1</td> <td>1</td> </tr> </tbody> </table> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;ELEELEELLL&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong></p> <p>Let&#39;s consider that there are 3 chairs in the waiting room. The table below shows the state of the waiting room at each second.</p> </div> <table> <tbody> <tr> <th>Second</th> <th>Event</th> <th>People in the Waiting Room</th> <th>Available Chairs</th> </tr> <tr> <td>0</td> <td>Enter</td> <td>1</td> <td>2</td> </tr> <tr> <td>1</td> <td>Leave</td> <td>0</td> <td>3</td> </tr> <tr> <td>2</td> <td>Enter</td> <td>1</td> <td>2</td> </tr> <tr> <td>3</td> <td>Enter</td> <td>2</td> <td>1</td> </tr> <tr> <td>4</td> <td>Leave</td> <td>1</td> <td>2</td> </tr> <tr> <td>5</td> <td>Enter</td> <td>2</td> <td>1</td> </tr> <tr> <td>6</td> <td>Enter</td> <td>3</td> <td>0</td> </tr> <tr> <td>7</td> <td>Leave</td> <td>2</td> <td>1</td> </tr> <tr> <td>8</td> <td>Leave</td> <td>1</td> <td>2</td> </tr> <tr> <td>9</td> <td>Leave</td> <td>0</td> <td>3</td> </tr> </tbody> </table> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 50</code></li> <li><code>s</code> consists only of the letters <code>&#39;E&#39;</code> and <code>&#39;L&#39;</code>.</li> <li><code>s</code> represents a valid sequence of entries and exits.</li> </ul>
String; Simulation
C++
class Solution { public: int minimumChairs(string s) { int cnt = 0, left = 0; for (char& c : s) { if (c == 'E') { if (left > 0) { --left; } else { ++cnt; } } else { ++left; } } return cnt; } };
3,168
Minimum Number of Chairs in a Waiting Room
Easy
<p>You are given a string <code>s</code>. Simulate events at each second <code>i</code>:</p> <ul> <li>If <code>s[i] == &#39;E&#39;</code>, a person enters the waiting room and takes one of the chairs in it.</li> <li>If <code>s[i] == &#39;L&#39;</code>, a person leaves the waiting room, freeing up a chair.</li> </ul> <p>Return the <strong>minimum </strong>number of chairs needed so that a chair is available for every person who enters the waiting room given that it is initially <strong>empty</strong>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;EEEEEEE&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">7</span></p> <p><strong>Explanation:</strong></p> <p>After each second, a person enters the waiting room and no person leaves it. Therefore, a minimum of 7 chairs is needed.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;ELELEEL&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>Let&#39;s consider that there are 2 chairs in the waiting room. The table below shows the state of the waiting room at each second.</p> </div> <table> <tbody> <tr> <th>Second</th> <th>Event</th> <th>People in the Waiting Room</th> <th>Available Chairs</th> </tr> <tr> <td>0</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>1</td> <td>Leave</td> <td>0</td> <td>2</td> </tr> <tr> <td>2</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>3</td> <td>Leave</td> <td>0</td> <td>2</td> </tr> <tr> <td>4</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>5</td> <td>Enter</td> <td>2</td> <td>0</td> </tr> <tr> <td>6</td> <td>Leave</td> <td>1</td> <td>1</td> </tr> </tbody> </table> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;ELEELEELLL&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong></p> <p>Let&#39;s consider that there are 3 chairs in the waiting room. The table below shows the state of the waiting room at each second.</p> </div> <table> <tbody> <tr> <th>Second</th> <th>Event</th> <th>People in the Waiting Room</th> <th>Available Chairs</th> </tr> <tr> <td>0</td> <td>Enter</td> <td>1</td> <td>2</td> </tr> <tr> <td>1</td> <td>Leave</td> <td>0</td> <td>3</td> </tr> <tr> <td>2</td> <td>Enter</td> <td>1</td> <td>2</td> </tr> <tr> <td>3</td> <td>Enter</td> <td>2</td> <td>1</td> </tr> <tr> <td>4</td> <td>Leave</td> <td>1</td> <td>2</td> </tr> <tr> <td>5</td> <td>Enter</td> <td>2</td> <td>1</td> </tr> <tr> <td>6</td> <td>Enter</td> <td>3</td> <td>0</td> </tr> <tr> <td>7</td> <td>Leave</td> <td>2</td> <td>1</td> </tr> <tr> <td>8</td> <td>Leave</td> <td>1</td> <td>2</td> </tr> <tr> <td>9</td> <td>Leave</td> <td>0</td> <td>3</td> </tr> </tbody> </table> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 50</code></li> <li><code>s</code> consists only of the letters <code>&#39;E&#39;</code> and <code>&#39;L&#39;</code>.</li> <li><code>s</code> represents a valid sequence of entries and exits.</li> </ul>
String; Simulation
Go
func minimumChairs(s string) int { cnt, left := 0, 0 for _, c := range s { if c == 'E' { if left > 0 { left-- } else { cnt++ } } else { left++ } } return cnt }
3,168
Minimum Number of Chairs in a Waiting Room
Easy
<p>You are given a string <code>s</code>. Simulate events at each second <code>i</code>:</p> <ul> <li>If <code>s[i] == &#39;E&#39;</code>, a person enters the waiting room and takes one of the chairs in it.</li> <li>If <code>s[i] == &#39;L&#39;</code>, a person leaves the waiting room, freeing up a chair.</li> </ul> <p>Return the <strong>minimum </strong>number of chairs needed so that a chair is available for every person who enters the waiting room given that it is initially <strong>empty</strong>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;EEEEEEE&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">7</span></p> <p><strong>Explanation:</strong></p> <p>After each second, a person enters the waiting room and no person leaves it. Therefore, a minimum of 7 chairs is needed.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;ELELEEL&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>Let&#39;s consider that there are 2 chairs in the waiting room. The table below shows the state of the waiting room at each second.</p> </div> <table> <tbody> <tr> <th>Second</th> <th>Event</th> <th>People in the Waiting Room</th> <th>Available Chairs</th> </tr> <tr> <td>0</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>1</td> <td>Leave</td> <td>0</td> <td>2</td> </tr> <tr> <td>2</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>3</td> <td>Leave</td> <td>0</td> <td>2</td> </tr> <tr> <td>4</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>5</td> <td>Enter</td> <td>2</td> <td>0</td> </tr> <tr> <td>6</td> <td>Leave</td> <td>1</td> <td>1</td> </tr> </tbody> </table> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;ELEELEELLL&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong></p> <p>Let&#39;s consider that there are 3 chairs in the waiting room. The table below shows the state of the waiting room at each second.</p> </div> <table> <tbody> <tr> <th>Second</th> <th>Event</th> <th>People in the Waiting Room</th> <th>Available Chairs</th> </tr> <tr> <td>0</td> <td>Enter</td> <td>1</td> <td>2</td> </tr> <tr> <td>1</td> <td>Leave</td> <td>0</td> <td>3</td> </tr> <tr> <td>2</td> <td>Enter</td> <td>1</td> <td>2</td> </tr> <tr> <td>3</td> <td>Enter</td> <td>2</td> <td>1</td> </tr> <tr> <td>4</td> <td>Leave</td> <td>1</td> <td>2</td> </tr> <tr> <td>5</td> <td>Enter</td> <td>2</td> <td>1</td> </tr> <tr> <td>6</td> <td>Enter</td> <td>3</td> <td>0</td> </tr> <tr> <td>7</td> <td>Leave</td> <td>2</td> <td>1</td> </tr> <tr> <td>8</td> <td>Leave</td> <td>1</td> <td>2</td> </tr> <tr> <td>9</td> <td>Leave</td> <td>0</td> <td>3</td> </tr> </tbody> </table> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 50</code></li> <li><code>s</code> consists only of the letters <code>&#39;E&#39;</code> and <code>&#39;L&#39;</code>.</li> <li><code>s</code> represents a valid sequence of entries and exits.</li> </ul>
String; Simulation
Java
class Solution { public int minimumChairs(String s) { int cnt = 0, left = 0; for (int i = 0; i < s.length(); ++i) { if (s.charAt(i) == 'E') { if (left > 0) { --left; } else { ++cnt; } } else { ++left; } } return cnt; } }
3,168
Minimum Number of Chairs in a Waiting Room
Easy
<p>You are given a string <code>s</code>. Simulate events at each second <code>i</code>:</p> <ul> <li>If <code>s[i] == &#39;E&#39;</code>, a person enters the waiting room and takes one of the chairs in it.</li> <li>If <code>s[i] == &#39;L&#39;</code>, a person leaves the waiting room, freeing up a chair.</li> </ul> <p>Return the <strong>minimum </strong>number of chairs needed so that a chair is available for every person who enters the waiting room given that it is initially <strong>empty</strong>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;EEEEEEE&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">7</span></p> <p><strong>Explanation:</strong></p> <p>After each second, a person enters the waiting room and no person leaves it. Therefore, a minimum of 7 chairs is needed.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;ELELEEL&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>Let&#39;s consider that there are 2 chairs in the waiting room. The table below shows the state of the waiting room at each second.</p> </div> <table> <tbody> <tr> <th>Second</th> <th>Event</th> <th>People in the Waiting Room</th> <th>Available Chairs</th> </tr> <tr> <td>0</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>1</td> <td>Leave</td> <td>0</td> <td>2</td> </tr> <tr> <td>2</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>3</td> <td>Leave</td> <td>0</td> <td>2</td> </tr> <tr> <td>4</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>5</td> <td>Enter</td> <td>2</td> <td>0</td> </tr> <tr> <td>6</td> <td>Leave</td> <td>1</td> <td>1</td> </tr> </tbody> </table> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;ELEELEELLL&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong></p> <p>Let&#39;s consider that there are 3 chairs in the waiting room. The table below shows the state of the waiting room at each second.</p> </div> <table> <tbody> <tr> <th>Second</th> <th>Event</th> <th>People in the Waiting Room</th> <th>Available Chairs</th> </tr> <tr> <td>0</td> <td>Enter</td> <td>1</td> <td>2</td> </tr> <tr> <td>1</td> <td>Leave</td> <td>0</td> <td>3</td> </tr> <tr> <td>2</td> <td>Enter</td> <td>1</td> <td>2</td> </tr> <tr> <td>3</td> <td>Enter</td> <td>2</td> <td>1</td> </tr> <tr> <td>4</td> <td>Leave</td> <td>1</td> <td>2</td> </tr> <tr> <td>5</td> <td>Enter</td> <td>2</td> <td>1</td> </tr> <tr> <td>6</td> <td>Enter</td> <td>3</td> <td>0</td> </tr> <tr> <td>7</td> <td>Leave</td> <td>2</td> <td>1</td> </tr> <tr> <td>8</td> <td>Leave</td> <td>1</td> <td>2</td> </tr> <tr> <td>9</td> <td>Leave</td> <td>0</td> <td>3</td> </tr> </tbody> </table> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 50</code></li> <li><code>s</code> consists only of the letters <code>&#39;E&#39;</code> and <code>&#39;L&#39;</code>.</li> <li><code>s</code> represents a valid sequence of entries and exits.</li> </ul>
String; Simulation
Python
class Solution: def minimumChairs(self, s: str) -> int: cnt = left = 0 for c in s: if c == "E": if left: left -= 1 else: cnt += 1 else: left += 1 return cnt
3,168
Minimum Number of Chairs in a Waiting Room
Easy
<p>You are given a string <code>s</code>. Simulate events at each second <code>i</code>:</p> <ul> <li>If <code>s[i] == &#39;E&#39;</code>, a person enters the waiting room and takes one of the chairs in it.</li> <li>If <code>s[i] == &#39;L&#39;</code>, a person leaves the waiting room, freeing up a chair.</li> </ul> <p>Return the <strong>minimum </strong>number of chairs needed so that a chair is available for every person who enters the waiting room given that it is initially <strong>empty</strong>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;EEEEEEE&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">7</span></p> <p><strong>Explanation:</strong></p> <p>After each second, a person enters the waiting room and no person leaves it. Therefore, a minimum of 7 chairs is needed.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;ELELEEL&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>Let&#39;s consider that there are 2 chairs in the waiting room. The table below shows the state of the waiting room at each second.</p> </div> <table> <tbody> <tr> <th>Second</th> <th>Event</th> <th>People in the Waiting Room</th> <th>Available Chairs</th> </tr> <tr> <td>0</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>1</td> <td>Leave</td> <td>0</td> <td>2</td> </tr> <tr> <td>2</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>3</td> <td>Leave</td> <td>0</td> <td>2</td> </tr> <tr> <td>4</td> <td>Enter</td> <td>1</td> <td>1</td> </tr> <tr> <td>5</td> <td>Enter</td> <td>2</td> <td>0</td> </tr> <tr> <td>6</td> <td>Leave</td> <td>1</td> <td>1</td> </tr> </tbody> </table> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;ELEELEELLL&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong></p> <p>Let&#39;s consider that there are 3 chairs in the waiting room. The table below shows the state of the waiting room at each second.</p> </div> <table> <tbody> <tr> <th>Second</th> <th>Event</th> <th>People in the Waiting Room</th> <th>Available Chairs</th> </tr> <tr> <td>0</td> <td>Enter</td> <td>1</td> <td>2</td> </tr> <tr> <td>1</td> <td>Leave</td> <td>0</td> <td>3</td> </tr> <tr> <td>2</td> <td>Enter</td> <td>1</td> <td>2</td> </tr> <tr> <td>3</td> <td>Enter</td> <td>2</td> <td>1</td> </tr> <tr> <td>4</td> <td>Leave</td> <td>1</td> <td>2</td> </tr> <tr> <td>5</td> <td>Enter</td> <td>2</td> <td>1</td> </tr> <tr> <td>6</td> <td>Enter</td> <td>3</td> <td>0</td> </tr> <tr> <td>7</td> <td>Leave</td> <td>2</td> <td>1</td> </tr> <tr> <td>8</td> <td>Leave</td> <td>1</td> <td>2</td> </tr> <tr> <td>9</td> <td>Leave</td> <td>0</td> <td>3</td> </tr> </tbody> </table> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 50</code></li> <li><code>s</code> consists only of the letters <code>&#39;E&#39;</code> and <code>&#39;L&#39;</code>.</li> <li><code>s</code> represents a valid sequence of entries and exits.</li> </ul>
String; Simulation
TypeScript
function minimumChairs(s: string): number { let [cnt, left] = [0, 0]; for (const c of s) { if (c === 'E') { if (left > 0) { --left; } else { ++cnt; } } else { ++left; } } return cnt; }
3,169
Count Days Without Meetings
Medium
<p>You are given a positive integer <code>days</code> representing the total number of days an employee is available for work (starting from day 1). You are also given a 2D array <code>meetings</code> of size <code>n</code> where, <code>meetings[i] = [start_i, end_i]</code> represents the starting and ending days of meeting <code>i</code> (inclusive).</p> <p>Return the count of days when the employee is available for work but no meetings are scheduled.</p> <p><strong>Note: </strong>The meetings may overlap.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 10, meetings = [[5,7],[1,3],[9,10]]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 4<sup>th</sup> and 8<sup>th</sup> days.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 5, meetings = [[2,4],[1,3]]</span></p> <p><strong>Output:</strong> <span class="example-io">1</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 5<sup>th </sup>day.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 6, meetings = [[1,6]]</span></p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong></p> <p>Meetings are scheduled for all working days.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= days &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= meetings.length &lt;= 10<sup>5</sup></code></li> <li><code>meetings[i].length == 2</code></li> <li><code><font face="monospace">1 &lt;= meetings[i][0] &lt;= meetings[i][1] &lt;= days</font></code></li> </ul>
Array; Sorting
C++
class Solution { public: int countDays(int days, vector<vector<int>>& meetings) { sort(meetings.begin(), meetings.end()); int ans = 0, last = 0; for (auto& e : meetings) { int st = e[0], ed = e[1]; if (last < st) { ans += st - last - 1; } last = max(last, ed); } ans += days - last; return ans; } };
3,169
Count Days Without Meetings
Medium
<p>You are given a positive integer <code>days</code> representing the total number of days an employee is available for work (starting from day 1). You are also given a 2D array <code>meetings</code> of size <code>n</code> where, <code>meetings[i] = [start_i, end_i]</code> represents the starting and ending days of meeting <code>i</code> (inclusive).</p> <p>Return the count of days when the employee is available for work but no meetings are scheduled.</p> <p><strong>Note: </strong>The meetings may overlap.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 10, meetings = [[5,7],[1,3],[9,10]]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 4<sup>th</sup> and 8<sup>th</sup> days.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 5, meetings = [[2,4],[1,3]]</span></p> <p><strong>Output:</strong> <span class="example-io">1</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 5<sup>th </sup>day.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 6, meetings = [[1,6]]</span></p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong></p> <p>Meetings are scheduled for all working days.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= days &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= meetings.length &lt;= 10<sup>5</sup></code></li> <li><code>meetings[i].length == 2</code></li> <li><code><font face="monospace">1 &lt;= meetings[i][0] &lt;= meetings[i][1] &lt;= days</font></code></li> </ul>
Array; Sorting
Go
func countDays(days int, meetings [][]int) (ans int) { sort.Slice(meetings, func(i, j int) bool { return meetings[i][0] < meetings[j][0] }) last := 0 for _, e := range meetings { st, ed := e[0], e[1] if last < st { ans += st - last - 1 } last = max(last, ed) } ans += days - last return }
3,169
Count Days Without Meetings
Medium
<p>You are given a positive integer <code>days</code> representing the total number of days an employee is available for work (starting from day 1). You are also given a 2D array <code>meetings</code> of size <code>n</code> where, <code>meetings[i] = [start_i, end_i]</code> represents the starting and ending days of meeting <code>i</code> (inclusive).</p> <p>Return the count of days when the employee is available for work but no meetings are scheduled.</p> <p><strong>Note: </strong>The meetings may overlap.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 10, meetings = [[5,7],[1,3],[9,10]]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 4<sup>th</sup> and 8<sup>th</sup> days.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 5, meetings = [[2,4],[1,3]]</span></p> <p><strong>Output:</strong> <span class="example-io">1</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 5<sup>th </sup>day.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 6, meetings = [[1,6]]</span></p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong></p> <p>Meetings are scheduled for all working days.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= days &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= meetings.length &lt;= 10<sup>5</sup></code></li> <li><code>meetings[i].length == 2</code></li> <li><code><font face="monospace">1 &lt;= meetings[i][0] &lt;= meetings[i][1] &lt;= days</font></code></li> </ul>
Array; Sorting
Java
class Solution { public int countDays(int days, int[][] meetings) { Arrays.sort(meetings, (a, b) -> a[0] - b[0]); int ans = 0, last = 0; for (var e : meetings) { int st = e[0], ed = e[1]; if (last < st) { ans += st - last - 1; } last = Math.max(last, ed); } ans += days - last; return ans; } }
3,169
Count Days Without Meetings
Medium
<p>You are given a positive integer <code>days</code> representing the total number of days an employee is available for work (starting from day 1). You are also given a 2D array <code>meetings</code> of size <code>n</code> where, <code>meetings[i] = [start_i, end_i]</code> represents the starting and ending days of meeting <code>i</code> (inclusive).</p> <p>Return the count of days when the employee is available for work but no meetings are scheduled.</p> <p><strong>Note: </strong>The meetings may overlap.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 10, meetings = [[5,7],[1,3],[9,10]]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 4<sup>th</sup> and 8<sup>th</sup> days.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 5, meetings = [[2,4],[1,3]]</span></p> <p><strong>Output:</strong> <span class="example-io">1</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 5<sup>th </sup>day.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 6, meetings = [[1,6]]</span></p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong></p> <p>Meetings are scheduled for all working days.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= days &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= meetings.length &lt;= 10<sup>5</sup></code></li> <li><code>meetings[i].length == 2</code></li> <li><code><font face="monospace">1 &lt;= meetings[i][0] &lt;= meetings[i][1] &lt;= days</font></code></li> </ul>
Array; Sorting
Python
class Solution: def countDays(self, days: int, meetings: List[List[int]]) -> int: meetings.sort() ans = last = 0 for st, ed in meetings: if last < st: ans += st - last - 1 last = max(last, ed) ans += days - last return ans
3,169
Count Days Without Meetings
Medium
<p>You are given a positive integer <code>days</code> representing the total number of days an employee is available for work (starting from day 1). You are also given a 2D array <code>meetings</code> of size <code>n</code> where, <code>meetings[i] = [start_i, end_i]</code> represents the starting and ending days of meeting <code>i</code> (inclusive).</p> <p>Return the count of days when the employee is available for work but no meetings are scheduled.</p> <p><strong>Note: </strong>The meetings may overlap.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 10, meetings = [[5,7],[1,3],[9,10]]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 4<sup>th</sup> and 8<sup>th</sup> days.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 5, meetings = [[2,4],[1,3]]</span></p> <p><strong>Output:</strong> <span class="example-io">1</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 5<sup>th </sup>day.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 6, meetings = [[1,6]]</span></p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong></p> <p>Meetings are scheduled for all working days.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= days &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= meetings.length &lt;= 10<sup>5</sup></code></li> <li><code>meetings[i].length == 2</code></li> <li><code><font face="monospace">1 &lt;= meetings[i][0] &lt;= meetings[i][1] &lt;= days</font></code></li> </ul>
Array; Sorting
Rust
impl Solution { pub fn count_days(days: i32, mut meetings: Vec<Vec<i32>>) -> i32 { meetings.sort_by_key(|m| m[0]); let mut ans = 0; let mut last = 0; for e in meetings { let st = e[0]; let ed = e[1]; if last < st { ans += st - last - 1; } last = last.max(ed); } ans + (days - last) } }
3,169
Count Days Without Meetings
Medium
<p>You are given a positive integer <code>days</code> representing the total number of days an employee is available for work (starting from day 1). You are also given a 2D array <code>meetings</code> of size <code>n</code> where, <code>meetings[i] = [start_i, end_i]</code> represents the starting and ending days of meeting <code>i</code> (inclusive).</p> <p>Return the count of days when the employee is available for work but no meetings are scheduled.</p> <p><strong>Note: </strong>The meetings may overlap.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 10, meetings = [[5,7],[1,3],[9,10]]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 4<sup>th</sup> and 8<sup>th</sup> days.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 5, meetings = [[2,4],[1,3]]</span></p> <p><strong>Output:</strong> <span class="example-io">1</span></p> <p><strong>Explanation:</strong></p> <p>There is no meeting scheduled on the 5<sup>th </sup>day.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">days = 6, meetings = [[1,6]]</span></p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong></p> <p>Meetings are scheduled for all working days.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= days &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= meetings.length &lt;= 10<sup>5</sup></code></li> <li><code>meetings[i].length == 2</code></li> <li><code><font face="monospace">1 &lt;= meetings[i][0] &lt;= meetings[i][1] &lt;= days</font></code></li> </ul>
Array; Sorting
TypeScript
function countDays(days: number, meetings: number[][]): number { meetings.sort((a, b) => a[0] - b[0]); let [ans, last] = [0, 0]; for (const [st, ed] of meetings) { if (last < st) { ans += st - last - 1; } last = Math.max(last, ed); } ans += days - last; return ans; }
3,170
Lexicographically Minimum String After Removing Stars
Medium
<p>You are given a string <code>s</code>. It may contain any number of <code>&#39;*&#39;</code> characters. Your task is to remove all <code>&#39;*&#39;</code> characters.</p> <p>While there is a <code>&#39;*&#39;</code>, do the following operation:</p> <ul> <li>Delete the leftmost <code>&#39;*&#39;</code> and the <strong>smallest</strong> non-<code>&#39;*&#39;</code> character to its <em>left</em>. If there are several smallest characters, you can delete any of them.</li> </ul> <p>Return the <span data-keyword="lexicographically-smaller-string">lexicographically smallest</span> resulting string after removing all <code>&#39;*&#39;</code> characters.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;aaba*&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;aab&quot;</span></p> <p><strong>Explanation:</strong></p> <p>We should delete one of the <code>&#39;a&#39;</code> characters with <code>&#39;*&#39;</code>. If we choose <code>s[3]</code>, <code>s</code> becomes the lexicographically smallest.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no <code>&#39;*&#39;</code> in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li> <li><code>s</code> consists only of lowercase English letters and <code>&#39;*&#39;</code>.</li> <li>The input is generated such that it is possible to delete all <code>&#39;*&#39;</code> characters.</li> </ul>
Stack; Greedy; Hash Table; String; Heap (Priority Queue)
C++
class Solution { public: string clearStars(string s) { stack<int> g[26]; int n = s.length(); vector<bool> rem(n); for (int i = 0; i < n; ++i) { if (s[i] == '*') { rem[i] = true; for (int j = 0; j < 26; ++j) { if (!g[j].empty()) { rem[g[j].top()] = true; g[j].pop(); break; } } } else { g[s[i] - 'a'].push(i); } } string ans; for (int i = 0; i < n; ++i) { if (!rem[i]) { ans.push_back(s[i]); } } return ans; } };
3,170
Lexicographically Minimum String After Removing Stars
Medium
<p>You are given a string <code>s</code>. It may contain any number of <code>&#39;*&#39;</code> characters. Your task is to remove all <code>&#39;*&#39;</code> characters.</p> <p>While there is a <code>&#39;*&#39;</code>, do the following operation:</p> <ul> <li>Delete the leftmost <code>&#39;*&#39;</code> and the <strong>smallest</strong> non-<code>&#39;*&#39;</code> character to its <em>left</em>. If there are several smallest characters, you can delete any of them.</li> </ul> <p>Return the <span data-keyword="lexicographically-smaller-string">lexicographically smallest</span> resulting string after removing all <code>&#39;*&#39;</code> characters.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;aaba*&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;aab&quot;</span></p> <p><strong>Explanation:</strong></p> <p>We should delete one of the <code>&#39;a&#39;</code> characters with <code>&#39;*&#39;</code>. If we choose <code>s[3]</code>, <code>s</code> becomes the lexicographically smallest.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no <code>&#39;*&#39;</code> in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li> <li><code>s</code> consists only of lowercase English letters and <code>&#39;*&#39;</code>.</li> <li>The input is generated such that it is possible to delete all <code>&#39;*&#39;</code> characters.</li> </ul>
Stack; Greedy; Hash Table; String; Heap (Priority Queue)
C#
public class Solution { public string ClearStars(string s) { int n = s.Length; List<int>[] g = new List<int>[26]; for (int i = 0; i < 26; i++) { g[i] = new List<int>(); } bool[] rem = new bool[n]; for (int i = 0; i < n; i++) { char ch = s[i]; if (ch == '*') { rem[i] = true; for (int j = 0; j < 26; j++) { if (g[j].Count > 0) { int idx = g[j][g[j].Count - 1]; g[j].RemoveAt(g[j].Count - 1); rem[idx] = true; break; } } } else { g[ch - 'a'].Add(i); } } var ans = new System.Text.StringBuilder(); for (int i = 0; i < n; i++) { if (!rem[i]) { ans.Append(s[i]); } } return ans.ToString(); } }
3,170
Lexicographically Minimum String After Removing Stars
Medium
<p>You are given a string <code>s</code>. It may contain any number of <code>&#39;*&#39;</code> characters. Your task is to remove all <code>&#39;*&#39;</code> characters.</p> <p>While there is a <code>&#39;*&#39;</code>, do the following operation:</p> <ul> <li>Delete the leftmost <code>&#39;*&#39;</code> and the <strong>smallest</strong> non-<code>&#39;*&#39;</code> character to its <em>left</em>. If there are several smallest characters, you can delete any of them.</li> </ul> <p>Return the <span data-keyword="lexicographically-smaller-string">lexicographically smallest</span> resulting string after removing all <code>&#39;*&#39;</code> characters.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;aaba*&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;aab&quot;</span></p> <p><strong>Explanation:</strong></p> <p>We should delete one of the <code>&#39;a&#39;</code> characters with <code>&#39;*&#39;</code>. If we choose <code>s[3]</code>, <code>s</code> becomes the lexicographically smallest.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no <code>&#39;*&#39;</code> in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li> <li><code>s</code> consists only of lowercase English letters and <code>&#39;*&#39;</code>.</li> <li>The input is generated such that it is possible to delete all <code>&#39;*&#39;</code> characters.</li> </ul>
Stack; Greedy; Hash Table; String; Heap (Priority Queue)
Go
func clearStars(s string) string { g := make([][]int, 26) n := len(s) rem := make([]bool, n) for i, c := range s { if c == '*' { rem[i] = true for j := 0; j < 26; j++ { if len(g[j]) > 0 { rem[g[j][len(g[j])-1]] = true g[j] = g[j][:len(g[j])-1] break } } } else { g[c-'a'] = append(g[c-'a'], i) } } ans := []byte{} for i := range s { if !rem[i] { ans = append(ans, s[i]) } } return string(ans) }
3,170
Lexicographically Minimum String After Removing Stars
Medium
<p>You are given a string <code>s</code>. It may contain any number of <code>&#39;*&#39;</code> characters. Your task is to remove all <code>&#39;*&#39;</code> characters.</p> <p>While there is a <code>&#39;*&#39;</code>, do the following operation:</p> <ul> <li>Delete the leftmost <code>&#39;*&#39;</code> and the <strong>smallest</strong> non-<code>&#39;*&#39;</code> character to its <em>left</em>. If there are several smallest characters, you can delete any of them.</li> </ul> <p>Return the <span data-keyword="lexicographically-smaller-string">lexicographically smallest</span> resulting string after removing all <code>&#39;*&#39;</code> characters.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;aaba*&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;aab&quot;</span></p> <p><strong>Explanation:</strong></p> <p>We should delete one of the <code>&#39;a&#39;</code> characters with <code>&#39;*&#39;</code>. If we choose <code>s[3]</code>, <code>s</code> becomes the lexicographically smallest.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no <code>&#39;*&#39;</code> in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li> <li><code>s</code> consists only of lowercase English letters and <code>&#39;*&#39;</code>.</li> <li>The input is generated such that it is possible to delete all <code>&#39;*&#39;</code> characters.</li> </ul>
Stack; Greedy; Hash Table; String; Heap (Priority Queue)
Java
class Solution { public String clearStars(String s) { Deque<Integer>[] g = new Deque[26]; Arrays.setAll(g, k -> new ArrayDeque<>()); int n = s.length(); boolean[] rem = new boolean[n]; for (int i = 0; i < n; ++i) { if (s.charAt(i) == '*') { rem[i] = true; for (int j = 0; j < 26; ++j) { if (!g[j].isEmpty()) { rem[g[j].pop()] = true; break; } } } else { g[s.charAt(i) - 'a'].push(i); } } StringBuilder sb = new StringBuilder(); for (int i = 0; i < n; ++i) { if (!rem[i]) { sb.append(s.charAt(i)); } } return sb.toString(); } }
3,170
Lexicographically Minimum String After Removing Stars
Medium
<p>You are given a string <code>s</code>. It may contain any number of <code>&#39;*&#39;</code> characters. Your task is to remove all <code>&#39;*&#39;</code> characters.</p> <p>While there is a <code>&#39;*&#39;</code>, do the following operation:</p> <ul> <li>Delete the leftmost <code>&#39;*&#39;</code> and the <strong>smallest</strong> non-<code>&#39;*&#39;</code> character to its <em>left</em>. If there are several smallest characters, you can delete any of them.</li> </ul> <p>Return the <span data-keyword="lexicographically-smaller-string">lexicographically smallest</span> resulting string after removing all <code>&#39;*&#39;</code> characters.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;aaba*&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;aab&quot;</span></p> <p><strong>Explanation:</strong></p> <p>We should delete one of the <code>&#39;a&#39;</code> characters with <code>&#39;*&#39;</code>. If we choose <code>s[3]</code>, <code>s</code> becomes the lexicographically smallest.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no <code>&#39;*&#39;</code> in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li> <li><code>s</code> consists only of lowercase English letters and <code>&#39;*&#39;</code>.</li> <li>The input is generated such that it is possible to delete all <code>&#39;*&#39;</code> characters.</li> </ul>
Stack; Greedy; Hash Table; String; Heap (Priority Queue)
Python
class Solution: def clearStars(self, s: str) -> str: g = defaultdict(list) n = len(s) rem = [False] * n for i, c in enumerate(s): if c == "*": rem[i] = True for a in ascii_lowercase: if g[a]: rem[g[a].pop()] = True break else: g[c].append(i) return "".join(c for i, c in enumerate(s) if not rem[i])
3,170
Lexicographically Minimum String After Removing Stars
Medium
<p>You are given a string <code>s</code>. It may contain any number of <code>&#39;*&#39;</code> characters. Your task is to remove all <code>&#39;*&#39;</code> characters.</p> <p>While there is a <code>&#39;*&#39;</code>, do the following operation:</p> <ul> <li>Delete the leftmost <code>&#39;*&#39;</code> and the <strong>smallest</strong> non-<code>&#39;*&#39;</code> character to its <em>left</em>. If there are several smallest characters, you can delete any of them.</li> </ul> <p>Return the <span data-keyword="lexicographically-smaller-string">lexicographically smallest</span> resulting string after removing all <code>&#39;*&#39;</code> characters.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;aaba*&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;aab&quot;</span></p> <p><strong>Explanation:</strong></p> <p>We should delete one of the <code>&#39;a&#39;</code> characters with <code>&#39;*&#39;</code>. If we choose <code>s[3]</code>, <code>s</code> becomes the lexicographically smallest.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no <code>&#39;*&#39;</code> in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li> <li><code>s</code> consists only of lowercase English letters and <code>&#39;*&#39;</code>.</li> <li>The input is generated such that it is possible to delete all <code>&#39;*&#39;</code> characters.</li> </ul>
Stack; Greedy; Hash Table; String; Heap (Priority Queue)
Rust
impl Solution { pub fn clear_stars(s: String) -> String { let n = s.len(); let s_bytes = s.as_bytes(); let mut g: Vec<Vec<usize>> = vec![vec![]; 26]; let mut rem = vec![false; n]; let chars: Vec<char> = s.chars().collect(); for (i, &ch) in chars.iter().enumerate() { if ch == '*' { rem[i] = true; for j in 0..26 { if let Some(idx) = g[j].pop() { rem[idx] = true; break; } } } else { g[(ch as u8 - b'a') as usize].push(i); } } chars .into_iter() .enumerate() .filter_map(|(i, ch)| if !rem[i] { Some(ch) } else { None }) .collect() } }
3,170
Lexicographically Minimum String After Removing Stars
Medium
<p>You are given a string <code>s</code>. It may contain any number of <code>&#39;*&#39;</code> characters. Your task is to remove all <code>&#39;*&#39;</code> characters.</p> <p>While there is a <code>&#39;*&#39;</code>, do the following operation:</p> <ul> <li>Delete the leftmost <code>&#39;*&#39;</code> and the <strong>smallest</strong> non-<code>&#39;*&#39;</code> character to its <em>left</em>. If there are several smallest characters, you can delete any of them.</li> </ul> <p>Return the <span data-keyword="lexicographically-smaller-string">lexicographically smallest</span> resulting string after removing all <code>&#39;*&#39;</code> characters.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;aaba*&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;aab&quot;</span></p> <p><strong>Explanation:</strong></p> <p>We should delete one of the <code>&#39;a&#39;</code> characters with <code>&#39;*&#39;</code>. If we choose <code>s[3]</code>, <code>s</code> becomes the lexicographically smallest.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no <code>&#39;*&#39;</code> in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li> <li><code>s</code> consists only of lowercase English letters and <code>&#39;*&#39;</code>.</li> <li>The input is generated such that it is possible to delete all <code>&#39;*&#39;</code> characters.</li> </ul>
Stack; Greedy; Hash Table; String; Heap (Priority Queue)
TypeScript
function clearStars(s: string): string { const g: number[][] = Array.from({ length: 26 }, () => []); const n = s.length; const rem: boolean[] = Array(n).fill(false); for (let i = 0; i < n; ++i) { if (s[i] === '*') { rem[i] = true; for (let j = 0; j < 26; ++j) { if (g[j].length) { rem[g[j].pop()!] = true; break; } } } else { g[s.charCodeAt(i) - 97].push(i); } } return s .split('') .filter((_, i) => !rem[i]) .join(''); }
3,171
Find Subarray With Bitwise OR Closest to K
Hard
<p>You are given an array <code>nums</code> and an integer <code>k</code>. You need to find a <span data-keyword="subarray-nonempty">subarray</span> of <code>nums</code> such that the <strong>absolute difference</strong> between <code>k</code> and the bitwise <code>OR</code> of the subarray elements is as<strong> small</strong> as possible. In other words, select a subarray <code>nums[l..r]</code> such that <code>|k - (nums[l] OR nums[l + 1] ... OR nums[r])|</code> is minimum.</p> <p>Return the <strong>minimum</strong> possible value of the absolute difference.</p> <p>A <strong>subarray</strong> is a contiguous <b>non-empty</b> sequence of elements within an array.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,4,5], k = 3</span></p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong></p> <p>The subarray <code>nums[0..1]</code> has <code>OR</code> value 3, which gives the minimum absolute difference <code>|3 - 3| = 0</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,3,1,3], k = 2</span></p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong></p> <p>The subarray <code>nums[1..1]</code> has <code>OR</code> value 3, which gives the minimum absolute difference <code>|3 - 2| = 1</code>.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1], k = 10</span></p> <p><strong>Output:</strong> <span class="example-io">9</span></p> <p><strong>Explanation:</strong></p> <p>There is a single subarray with <code>OR</code> value 1, which gives the minimum absolute difference <code>|10 - 1| = 9</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>9</sup></code></li> </ul>
Bit Manipulation; Segment Tree; Array; Binary Search
C++
class Solution { public: int minimumDifference(vector<int>& nums, int k) { int mx = *max_element(nums.begin(), nums.end()); int m = 32 - __builtin_clz(mx); int n = nums.size(); int ans = INT_MAX; vector<int> cnt(m); for (int i = 0, j = 0, s = 0; j < n; ++j) { s |= nums[j]; ans = min(ans, abs(s - k)); for (int h = 0; h < m; ++h) { if (nums[j] >> h & 1) { ++cnt[h]; } } while (i < j && s > k) { for (int h = 0; h < m; ++h) { if (nums[i] >> h & 1 && --cnt[h] == 0) { s ^= 1 << h; } } ans = min(ans, abs(s - k)); ++i; } } return ans; } };
3,171
Find Subarray With Bitwise OR Closest to K
Hard
<p>You are given an array <code>nums</code> and an integer <code>k</code>. You need to find a <span data-keyword="subarray-nonempty">subarray</span> of <code>nums</code> such that the <strong>absolute difference</strong> between <code>k</code> and the bitwise <code>OR</code> of the subarray elements is as<strong> small</strong> as possible. In other words, select a subarray <code>nums[l..r]</code> such that <code>|k - (nums[l] OR nums[l + 1] ... OR nums[r])|</code> is minimum.</p> <p>Return the <strong>minimum</strong> possible value of the absolute difference.</p> <p>A <strong>subarray</strong> is a contiguous <b>non-empty</b> sequence of elements within an array.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,4,5], k = 3</span></p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong></p> <p>The subarray <code>nums[0..1]</code> has <code>OR</code> value 3, which gives the minimum absolute difference <code>|3 - 3| = 0</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,3,1,3], k = 2</span></p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong></p> <p>The subarray <code>nums[1..1]</code> has <code>OR</code> value 3, which gives the minimum absolute difference <code>|3 - 2| = 1</code>.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1], k = 10</span></p> <p><strong>Output:</strong> <span class="example-io">9</span></p> <p><strong>Explanation:</strong></p> <p>There is a single subarray with <code>OR</code> value 1, which gives the minimum absolute difference <code>|10 - 1| = 9</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>9</sup></code></li> </ul>
Bit Manipulation; Segment Tree; Array; Binary Search
Go
func minimumDifference(nums []int, k int) int { m := bits.Len(uint(slices.Max(nums))) cnt := make([]int, m) ans := math.MaxInt32 s, i := 0, 0 for j, x := range nums { s |= x ans = min(ans, abs(s-k)) for h := 0; h < m; h++ { if x>>h&1 == 1 { cnt[h]++ } } for i < j && s > k { y := nums[i] for h := 0; h < m; h++ { if y>>h&1 == 1 { cnt[h]-- if cnt[h] == 0 { s ^= 1 << h } } } ans = min(ans, abs(s-k)) i++ } } return ans } func abs(x int) int { if x < 0 { return -x } return x }
3,171
Find Subarray With Bitwise OR Closest to K
Hard
<p>You are given an array <code>nums</code> and an integer <code>k</code>. You need to find a <span data-keyword="subarray-nonempty">subarray</span> of <code>nums</code> such that the <strong>absolute difference</strong> between <code>k</code> and the bitwise <code>OR</code> of the subarray elements is as<strong> small</strong> as possible. In other words, select a subarray <code>nums[l..r]</code> such that <code>|k - (nums[l] OR nums[l + 1] ... OR nums[r])|</code> is minimum.</p> <p>Return the <strong>minimum</strong> possible value of the absolute difference.</p> <p>A <strong>subarray</strong> is a contiguous <b>non-empty</b> sequence of elements within an array.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,4,5], k = 3</span></p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong></p> <p>The subarray <code>nums[0..1]</code> has <code>OR</code> value 3, which gives the minimum absolute difference <code>|3 - 3| = 0</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,3,1,3], k = 2</span></p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong></p> <p>The subarray <code>nums[1..1]</code> has <code>OR</code> value 3, which gives the minimum absolute difference <code>|3 - 2| = 1</code>.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1], k = 10</span></p> <p><strong>Output:</strong> <span class="example-io">9</span></p> <p><strong>Explanation:</strong></p> <p>There is a single subarray with <code>OR</code> value 1, which gives the minimum absolute difference <code>|10 - 1| = 9</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>9</sup></code></li> </ul>
Bit Manipulation; Segment Tree; Array; Binary Search
Java
class Solution { public int minimumDifference(int[] nums, int k) { int mx = 0; for (int x : nums) { mx = Math.max(mx, x); } int m = 32 - Integer.numberOfLeadingZeros(mx); int[] cnt = new int[m]; int n = nums.length; int ans = Integer.MAX_VALUE; for (int i = 0, j = 0, s = 0; j < n; ++j) { s |= nums[j]; ans = Math.min(ans, Math.abs(s - k)); for (int h = 0; h < m; ++h) { if ((nums[j] >> h & 1) == 1) { ++cnt[h]; } } while (i < j && s > k) { for (int h = 0; h < m; ++h) { if ((nums[i] >> h & 1) == 1 && --cnt[h] == 0) { s ^= 1 << h; } } ++i; ans = Math.min(ans, Math.abs(s - k)); } } return ans; } }
3,171
Find Subarray With Bitwise OR Closest to K
Hard
<p>You are given an array <code>nums</code> and an integer <code>k</code>. You need to find a <span data-keyword="subarray-nonempty">subarray</span> of <code>nums</code> such that the <strong>absolute difference</strong> between <code>k</code> and the bitwise <code>OR</code> of the subarray elements is as<strong> small</strong> as possible. In other words, select a subarray <code>nums[l..r]</code> such that <code>|k - (nums[l] OR nums[l + 1] ... OR nums[r])|</code> is minimum.</p> <p>Return the <strong>minimum</strong> possible value of the absolute difference.</p> <p>A <strong>subarray</strong> is a contiguous <b>non-empty</b> sequence of elements within an array.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,4,5], k = 3</span></p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong></p> <p>The subarray <code>nums[0..1]</code> has <code>OR</code> value 3, which gives the minimum absolute difference <code>|3 - 3| = 0</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,3,1,3], k = 2</span></p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong></p> <p>The subarray <code>nums[1..1]</code> has <code>OR</code> value 3, which gives the minimum absolute difference <code>|3 - 2| = 1</code>.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1], k = 10</span></p> <p><strong>Output:</strong> <span class="example-io">9</span></p> <p><strong>Explanation:</strong></p> <p>There is a single subarray with <code>OR</code> value 1, which gives the minimum absolute difference <code>|10 - 1| = 9</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>9</sup></code></li> </ul>
Bit Manipulation; Segment Tree; Array; Binary Search
Python
class Solution: def minimumDifference(self, nums: List[int], k: int) -> int: m = max(nums).bit_length() cnt = [0] * m s = i = 0 ans = inf for j, x in enumerate(nums): s |= x ans = min(ans, abs(s - k)) for h in range(m): if x >> h & 1: cnt[h] += 1 while i < j and s > k: y = nums[i] for h in range(m): if y >> h & 1: cnt[h] -= 1 if cnt[h] == 0: s ^= 1 << h i += 1 ans = min(ans, abs(s - k)) return ans
3,171
Find Subarray With Bitwise OR Closest to K
Hard
<p>You are given an array <code>nums</code> and an integer <code>k</code>. You need to find a <span data-keyword="subarray-nonempty">subarray</span> of <code>nums</code> such that the <strong>absolute difference</strong> between <code>k</code> and the bitwise <code>OR</code> of the subarray elements is as<strong> small</strong> as possible. In other words, select a subarray <code>nums[l..r]</code> such that <code>|k - (nums[l] OR nums[l + 1] ... OR nums[r])|</code> is minimum.</p> <p>Return the <strong>minimum</strong> possible value of the absolute difference.</p> <p>A <strong>subarray</strong> is a contiguous <b>non-empty</b> sequence of elements within an array.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,4,5], k = 3</span></p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong></p> <p>The subarray <code>nums[0..1]</code> has <code>OR</code> value 3, which gives the minimum absolute difference <code>|3 - 3| = 0</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,3,1,3], k = 2</span></p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong></p> <p>The subarray <code>nums[1..1]</code> has <code>OR</code> value 3, which gives the minimum absolute difference <code>|3 - 2| = 1</code>.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1], k = 10</span></p> <p><strong>Output:</strong> <span class="example-io">9</span></p> <p><strong>Explanation:</strong></p> <p>There is a single subarray with <code>OR</code> value 1, which gives the minimum absolute difference <code>|10 - 1| = 9</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>9</sup></code></li> </ul>
Bit Manipulation; Segment Tree; Array; Binary Search
TypeScript
function minimumDifference(nums: number[], k: number): number { const m = Math.max(...nums).toString(2).length; const n = nums.length; const cnt: number[] = Array(m).fill(0); let ans = Infinity; for (let i = 0, j = 0, s = 0; j < n; ++j) { s |= nums[j]; ans = Math.min(ans, Math.abs(s - k)); for (let h = 0; h < m; ++h) { if ((nums[j] >> h) & 1) { ++cnt[h]; } } while (i < j && s > k) { for (let h = 0; h < m; ++h) { if ((nums[i] >> h) & 1 && --cnt[h] === 0) { s ^= 1 << h; } } ans = Math.min(ans, Math.abs(s - k)); ++i; } } return ans; }
3,172
Second Day Verification
Easy
<p>Table: <code>emails</code></p> <pre> +-------------+----------+ | Column Name | Type | +-------------+----------+ | email_id | int | | user_id | int | | signup_date | datetime | +-------------+----------+ (email_id, user_id) is the primary key (combination of columns with unique values) for this table. Each row of this table contains the email ID, user ID, and signup date. </pre> <p>Table: <code>texts</code></p> <pre> +---------------+----------+ | Column Name | Type | +---------------+----------+ | text_id | int | | email_id | int | | signup_action | enum | | action_date | datetime | +---------------+----------+ (text_id, email_id) is the primary key (combination of columns with unique values) for this table. signup_action is an enum type of (&#39;Verified&#39;, &#39;Not Verified&#39;). Each row of this table contains the text ID, email ID, signup action, and action date. </pre> <p>Write a Solution to find the user IDs of those who <strong>verified</strong> their <strong>sign-up</strong> on the <strong>second day</strong>.</p> <p>Return <em>the result table ordered by</em> <code>user_id</code> <em>in <strong>ascending</strong> order</em>.</p> <p>The result format is in the following example.</p> <p>&nbsp;</p> <p><strong class="example">Example:</strong></p> <div class="example-block"> <p><strong>Input:</strong></p> <p>emails table:</p> <pre class="example-io"> +----------+---------+---------------------+ | email_id | user_id | signup_date | +----------+---------+---------------------+ | 125 | 7771 | 2022-06-14 09:30:00| | 433 | 1052 | 2022-07-09 08:15:00| | 234 | 7005 | 2022-08-20 10:00:00| +----------+---------+---------------------+ </pre> <p>texts table:</p> <pre class="example-io"> +---------+----------+--------------+---------------------+ | text_id | email_id | signup_action| action_date | +---------+----------+--------------+---------------------+ | 1 | 125 | Verified | 2022-06-15 08:30:00| | 2 | 433 | Not Verified | 2022-07-10 10:45:00| | 4 | 234 | Verified | 2022-08-21 09:30:00| +---------+----------+--------------+---------------------+ </pre> <p><strong>Output:</strong></p> <pre class="example-io"> +---------+ | user_id | +---------+ | 7005 | | 7771 | +---------+ </pre> <p><strong>Explanation:</strong></p> <ul> <li>User with user_id 7005 and email_id 234 signed up on 2022-08-20 10:00:00 and&nbsp;verified on second day of the signup.</li> <li>User with user_id 7771 and email_id 125 signed up on 2022-06-14 09:30:00 and&nbsp;verified on second day of the signup.</li> </ul> </div>
Database
SQL
# Write your MySQL query statement below SELECT user_id FROM Emails AS e JOIN texts AS t ON e.email_id = t.email_id AND DATEDIFF(action_date, signup_date) = 1 AND signup_action = 'Verified' ORDER BY 1;
3,173
Bitwise OR of Adjacent Elements
Easy
<p>Given an array <code>nums</code> of length <code>n</code>, return an array <code>answer</code> of length <code>n - 1</code> such that <code>answer[i] = nums[i] | nums[i + 1]</code> where <code>|</code> is the bitwise <code>OR</code> operation.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,3,7,15]</span></p> <p><strong>Output:</strong> <span class="example-io">[3,7,15]</span></p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [8,4,2]</span></p> <p><strong>Output:</strong> <span class="example-io">[12,6]</span></p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [5,4,9,11]</span></p> <p><strong>Output:</strong> <span class="example-io">[5,13,11]</span></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 &lt;= nums.length &lt;= 100</code></li> <li><code>0 &lt;= nums[i]&nbsp;&lt;= 100</code></li> </ul>
Bit Manipulation; Array
C++
class Solution { public: vector<int> orArray(vector<int>& nums) { int n = nums.size(); vector<int> ans(n - 1); for (int i = 0; i < n - 1; ++i) { ans[i] = nums[i] | nums[i + 1]; } return ans; } };
3,173
Bitwise OR of Adjacent Elements
Easy
<p>Given an array <code>nums</code> of length <code>n</code>, return an array <code>answer</code> of length <code>n - 1</code> such that <code>answer[i] = nums[i] | nums[i + 1]</code> where <code>|</code> is the bitwise <code>OR</code> operation.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,3,7,15]</span></p> <p><strong>Output:</strong> <span class="example-io">[3,7,15]</span></p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [8,4,2]</span></p> <p><strong>Output:</strong> <span class="example-io">[12,6]</span></p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [5,4,9,11]</span></p> <p><strong>Output:</strong> <span class="example-io">[5,13,11]</span></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 &lt;= nums.length &lt;= 100</code></li> <li><code>0 &lt;= nums[i]&nbsp;&lt;= 100</code></li> </ul>
Bit Manipulation; Array
Go
func orArray(nums []int) (ans []int) { for i, x := range nums[1:] { ans = append(ans, x|nums[i]) } return }
3,173
Bitwise OR of Adjacent Elements
Easy
<p>Given an array <code>nums</code> of length <code>n</code>, return an array <code>answer</code> of length <code>n - 1</code> such that <code>answer[i] = nums[i] | nums[i + 1]</code> where <code>|</code> is the bitwise <code>OR</code> operation.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,3,7,15]</span></p> <p><strong>Output:</strong> <span class="example-io">[3,7,15]</span></p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [8,4,2]</span></p> <p><strong>Output:</strong> <span class="example-io">[12,6]</span></p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [5,4,9,11]</span></p> <p><strong>Output:</strong> <span class="example-io">[5,13,11]</span></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 &lt;= nums.length &lt;= 100</code></li> <li><code>0 &lt;= nums[i]&nbsp;&lt;= 100</code></li> </ul>
Bit Manipulation; Array
Java
class Solution { public int[] orArray(int[] nums) { int n = nums.length; int[] ans = new int[n - 1]; for (int i = 0; i < n - 1; ++i) { ans[i] = nums[i] | nums[i + 1]; } return ans; } }
3,173
Bitwise OR of Adjacent Elements
Easy
<p>Given an array <code>nums</code> of length <code>n</code>, return an array <code>answer</code> of length <code>n - 1</code> such that <code>answer[i] = nums[i] | nums[i + 1]</code> where <code>|</code> is the bitwise <code>OR</code> operation.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,3,7,15]</span></p> <p><strong>Output:</strong> <span class="example-io">[3,7,15]</span></p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [8,4,2]</span></p> <p><strong>Output:</strong> <span class="example-io">[12,6]</span></p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [5,4,9,11]</span></p> <p><strong>Output:</strong> <span class="example-io">[5,13,11]</span></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 &lt;= nums.length &lt;= 100</code></li> <li><code>0 &lt;= nums[i]&nbsp;&lt;= 100</code></li> </ul>
Bit Manipulation; Array
Python
class Solution: def orArray(self, nums: List[int]) -> List[int]: return [a | b for a, b in pairwise(nums)]
3,173
Bitwise OR of Adjacent Elements
Easy
<p>Given an array <code>nums</code> of length <code>n</code>, return an array <code>answer</code> of length <code>n - 1</code> such that <code>answer[i] = nums[i] | nums[i + 1]</code> where <code>|</code> is the bitwise <code>OR</code> operation.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,3,7,15]</span></p> <p><strong>Output:</strong> <span class="example-io">[3,7,15]</span></p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [8,4,2]</span></p> <p><strong>Output:</strong> <span class="example-io">[12,6]</span></p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [5,4,9,11]</span></p> <p><strong>Output:</strong> <span class="example-io">[5,13,11]</span></p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 &lt;= nums.length &lt;= 100</code></li> <li><code>0 &lt;= nums[i]&nbsp;&lt;= 100</code></li> </ul>
Bit Manipulation; Array
TypeScript
function orArray(nums: number[]): number[] { return nums.slice(0, -1).map((v, i) => v | nums[i + 1]); }
3,174
Clear Digits
Easy
<p>You are given a string <code>s</code>.</p> <p>Your task is to remove <strong>all</strong> digits by doing this operation repeatedly:</p> <ul> <li>Delete the <em>first</em> digit and the <strong>closest</strong> <b>non-digit</b> character to its <em>left</em>.</li> </ul> <p>Return the resulting string after removing all digits.</p> <p><strong>Note</strong> that the operation <em>cannot</em> be performed on a digit that does not have any non-digit character to its left.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no digit in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;cb34&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;&quot;</span></p> <p><strong>Explanation:</strong></p> <p>First, we apply the operation on <code>s[2]</code>, and <code>s</code> becomes <code>&quot;c4&quot;</code>.</p> <p>Then we apply the operation on <code>s[1]</code>, and <code>s</code> becomes <code>&quot;&quot;</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 100</code></li> <li><code>s</code> consists only of lowercase English letters and digits.</li> <li>The input is generated such that it is possible to delete all digits.</li> </ul>
Stack; String; Simulation
C++
class Solution { public: string clearDigits(string s) { string stk; for (char c : s) { if (isdigit(c)) { stk.pop_back(); } else { stk.push_back(c); } } return stk; } };
3,174
Clear Digits
Easy
<p>You are given a string <code>s</code>.</p> <p>Your task is to remove <strong>all</strong> digits by doing this operation repeatedly:</p> <ul> <li>Delete the <em>first</em> digit and the <strong>closest</strong> <b>non-digit</b> character to its <em>left</em>.</li> </ul> <p>Return the resulting string after removing all digits.</p> <p><strong>Note</strong> that the operation <em>cannot</em> be performed on a digit that does not have any non-digit character to its left.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no digit in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;cb34&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;&quot;</span></p> <p><strong>Explanation:</strong></p> <p>First, we apply the operation on <code>s[2]</code>, and <code>s</code> becomes <code>&quot;c4&quot;</code>.</p> <p>Then we apply the operation on <code>s[1]</code>, and <code>s</code> becomes <code>&quot;&quot;</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 100</code></li> <li><code>s</code> consists only of lowercase English letters and digits.</li> <li>The input is generated such that it is possible to delete all digits.</li> </ul>
Stack; String; Simulation
Go
func clearDigits(s string) string { stk := []byte{} for i := range s { if s[i] >= '0' && s[i] <= '9' { stk = stk[:len(stk)-1] } else { stk = append(stk, s[i]) } } return string(stk) }
3,174
Clear Digits
Easy
<p>You are given a string <code>s</code>.</p> <p>Your task is to remove <strong>all</strong> digits by doing this operation repeatedly:</p> <ul> <li>Delete the <em>first</em> digit and the <strong>closest</strong> <b>non-digit</b> character to its <em>left</em>.</li> </ul> <p>Return the resulting string after removing all digits.</p> <p><strong>Note</strong> that the operation <em>cannot</em> be performed on a digit that does not have any non-digit character to its left.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no digit in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;cb34&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;&quot;</span></p> <p><strong>Explanation:</strong></p> <p>First, we apply the operation on <code>s[2]</code>, and <code>s</code> becomes <code>&quot;c4&quot;</code>.</p> <p>Then we apply the operation on <code>s[1]</code>, and <code>s</code> becomes <code>&quot;&quot;</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 100</code></li> <li><code>s</code> consists only of lowercase English letters and digits.</li> <li>The input is generated such that it is possible to delete all digits.</li> </ul>
Stack; String; Simulation
Java
class Solution { public String clearDigits(String s) { StringBuilder stk = new StringBuilder(); for (char c : s.toCharArray()) { if (Character.isDigit(c)) { stk.deleteCharAt(stk.length() - 1); } else { stk.append(c); } } return stk.toString(); } }
3,174
Clear Digits
Easy
<p>You are given a string <code>s</code>.</p> <p>Your task is to remove <strong>all</strong> digits by doing this operation repeatedly:</p> <ul> <li>Delete the <em>first</em> digit and the <strong>closest</strong> <b>non-digit</b> character to its <em>left</em>.</li> </ul> <p>Return the resulting string after removing all digits.</p> <p><strong>Note</strong> that the operation <em>cannot</em> be performed on a digit that does not have any non-digit character to its left.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no digit in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;cb34&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;&quot;</span></p> <p><strong>Explanation:</strong></p> <p>First, we apply the operation on <code>s[2]</code>, and <code>s</code> becomes <code>&quot;c4&quot;</code>.</p> <p>Then we apply the operation on <code>s[1]</code>, and <code>s</code> becomes <code>&quot;&quot;</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 100</code></li> <li><code>s</code> consists only of lowercase English letters and digits.</li> <li>The input is generated such that it is possible to delete all digits.</li> </ul>
Stack; String; Simulation
Python
class Solution: def clearDigits(self, s: str) -> str: stk = [] for c in s: if c.isdigit(): stk.pop() else: stk.append(c) return "".join(stk)
3,174
Clear Digits
Easy
<p>You are given a string <code>s</code>.</p> <p>Your task is to remove <strong>all</strong> digits by doing this operation repeatedly:</p> <ul> <li>Delete the <em>first</em> digit and the <strong>closest</strong> <b>non-digit</b> character to its <em>left</em>.</li> </ul> <p>Return the resulting string after removing all digits.</p> <p><strong>Note</strong> that the operation <em>cannot</em> be performed on a digit that does not have any non-digit character to its left.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;abc&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;abc&quot;</span></p> <p><strong>Explanation:</strong></p> <p>There is no digit in the string.<!-- notionvc: ff07e34f-b1d6-41fb-9f83-5d0ba3c1ecde --></p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">s = &quot;cb34&quot;</span></p> <p><strong>Output:</strong> <span class="example-io">&quot;&quot;</span></p> <p><strong>Explanation:</strong></p> <p>First, we apply the operation on <code>s[2]</code>, and <code>s</code> becomes <code>&quot;c4&quot;</code>.</p> <p>Then we apply the operation on <code>s[1]</code>, and <code>s</code> becomes <code>&quot;&quot;</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= s.length &lt;= 100</code></li> <li><code>s</code> consists only of lowercase English letters and digits.</li> <li>The input is generated such that it is possible to delete all digits.</li> </ul>
Stack; String; Simulation
TypeScript
function clearDigits(s: string): string { const stk: string[] = []; for (const c of s) { if (!isNaN(parseInt(c))) { stk.pop(); } else { stk.push(c); } } return stk.join(''); }
3,175
Find The First Player to win K Games in a Row
Medium
<p>A competition consists of <code>n</code> players numbered from <code>0</code> to <code>n - 1</code>.</p> <p>You are given an integer array <code>skills</code> of size <code>n</code> and a <strong>positive</strong> integer <code>k</code>, where <code>skills[i]</code> is the skill level of player <code>i</code>. All integers in <code>skills</code> are <strong>unique</strong>.</p> <p>All players are standing in a queue in order from player <code>0</code> to player <code>n - 1</code>.</p> <p>The competition process is as follows:</p> <ul> <li>The first two players in the queue play a game, and the player with the <strong>higher</strong> skill level wins.</li> <li>After the game, the winner stays at the beginning of the queue, and the loser goes to the end of it.</li> </ul> <p>The winner of the competition is the <strong>first</strong> player who wins <code>k</code> games <strong>in a row</strong>.</p> <p>Return the initial index of the <em>winning</em> player.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">skills = [4,2,6,3,9], k = 2</span></p> <p><strong>Output:</strong> 2</p> <p><strong>Explanation:</strong></p> <p>Initially, the queue of players is <code>[0,1,2,3,4]</code>. The following process happens:</p> <ul> <li>Players 0 and 1 play a game, since the skill of player 0 is higher than that of player 1, player 0 wins. The resulting queue is <code>[0,2,3,4,1]</code>.</li> <li>Players 0 and 2 play a game, since the skill of player 2 is higher than that of player 0, player 2 wins. The resulting queue is <code>[2,3,4,1,0]</code>.</li> <li>Players 2 and 3 play a game, since the skill of player 2 is higher than that of player 3, player 2 wins. The resulting queue is <code>[2,4,1,0,3]</code>.</li> </ul> <p>Player 2 won <code>k = 2</code> games in a row, so the winner is player 2.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">skills = [2,5,4], k = 3</span></p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong></p> <p>Initially, the queue of players is <code>[0,1,2]</code>. The following process happens:</p> <ul> <li>Players 0 and 1 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is <code>[1,2,0]</code>.</li> <li>Players 1 and 2 play a game, since the skill of player 1 is higher than that of player 2, player 1 wins. The resulting queue is <code>[1,0,2]</code>.</li> <li>Players 1 and 0 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is <code>[1,2,0]</code>.</li> </ul> <p>Player 1 won <code>k = 3</code> games in a row, so the winner is player 1.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>n == skills.length</code></li> <li><code>2 &lt;= n &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= skills[i] &lt;= 10<sup>6</sup></code></li> <li>All integers in <code>skills</code> are unique.</li> </ul>
Array; Simulation
C++
class Solution { public: int findWinningPlayer(vector<int>& skills, int k) { int n = skills.size(); k = min(k, n - 1); int i = 0, cnt = 0; for (int j = 1; j < n; ++j) { if (skills[i] < skills[j]) { i = j; cnt = 1; } else { ++cnt; } if (cnt == k) { break; } } return i; } };
3,175
Find The First Player to win K Games in a Row
Medium
<p>A competition consists of <code>n</code> players numbered from <code>0</code> to <code>n - 1</code>.</p> <p>You are given an integer array <code>skills</code> of size <code>n</code> and a <strong>positive</strong> integer <code>k</code>, where <code>skills[i]</code> is the skill level of player <code>i</code>. All integers in <code>skills</code> are <strong>unique</strong>.</p> <p>All players are standing in a queue in order from player <code>0</code> to player <code>n - 1</code>.</p> <p>The competition process is as follows:</p> <ul> <li>The first two players in the queue play a game, and the player with the <strong>higher</strong> skill level wins.</li> <li>After the game, the winner stays at the beginning of the queue, and the loser goes to the end of it.</li> </ul> <p>The winner of the competition is the <strong>first</strong> player who wins <code>k</code> games <strong>in a row</strong>.</p> <p>Return the initial index of the <em>winning</em> player.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">skills = [4,2,6,3,9], k = 2</span></p> <p><strong>Output:</strong> 2</p> <p><strong>Explanation:</strong></p> <p>Initially, the queue of players is <code>[0,1,2,3,4]</code>. The following process happens:</p> <ul> <li>Players 0 and 1 play a game, since the skill of player 0 is higher than that of player 1, player 0 wins. The resulting queue is <code>[0,2,3,4,1]</code>.</li> <li>Players 0 and 2 play a game, since the skill of player 2 is higher than that of player 0, player 2 wins. The resulting queue is <code>[2,3,4,1,0]</code>.</li> <li>Players 2 and 3 play a game, since the skill of player 2 is higher than that of player 3, player 2 wins. The resulting queue is <code>[2,4,1,0,3]</code>.</li> </ul> <p>Player 2 won <code>k = 2</code> games in a row, so the winner is player 2.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">skills = [2,5,4], k = 3</span></p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong></p> <p>Initially, the queue of players is <code>[0,1,2]</code>. The following process happens:</p> <ul> <li>Players 0 and 1 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is <code>[1,2,0]</code>.</li> <li>Players 1 and 2 play a game, since the skill of player 1 is higher than that of player 2, player 1 wins. The resulting queue is <code>[1,0,2]</code>.</li> <li>Players 1 and 0 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is <code>[1,2,0]</code>.</li> </ul> <p>Player 1 won <code>k = 3</code> games in a row, so the winner is player 1.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>n == skills.length</code></li> <li><code>2 &lt;= n &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= skills[i] &lt;= 10<sup>6</sup></code></li> <li>All integers in <code>skills</code> are unique.</li> </ul>
Array; Simulation
Go
func findWinningPlayer(skills []int, k int) int { n := len(skills) k = min(k, n-1) i, cnt := 0, 0 for j := 1; j < n; j++ { if skills[i] < skills[j] { i = j cnt = 1 } else { cnt++ } if cnt == k { break } } return i }
3,175
Find The First Player to win K Games in a Row
Medium
<p>A competition consists of <code>n</code> players numbered from <code>0</code> to <code>n - 1</code>.</p> <p>You are given an integer array <code>skills</code> of size <code>n</code> and a <strong>positive</strong> integer <code>k</code>, where <code>skills[i]</code> is the skill level of player <code>i</code>. All integers in <code>skills</code> are <strong>unique</strong>.</p> <p>All players are standing in a queue in order from player <code>0</code> to player <code>n - 1</code>.</p> <p>The competition process is as follows:</p> <ul> <li>The first two players in the queue play a game, and the player with the <strong>higher</strong> skill level wins.</li> <li>After the game, the winner stays at the beginning of the queue, and the loser goes to the end of it.</li> </ul> <p>The winner of the competition is the <strong>first</strong> player who wins <code>k</code> games <strong>in a row</strong>.</p> <p>Return the initial index of the <em>winning</em> player.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">skills = [4,2,6,3,9], k = 2</span></p> <p><strong>Output:</strong> 2</p> <p><strong>Explanation:</strong></p> <p>Initially, the queue of players is <code>[0,1,2,3,4]</code>. The following process happens:</p> <ul> <li>Players 0 and 1 play a game, since the skill of player 0 is higher than that of player 1, player 0 wins. The resulting queue is <code>[0,2,3,4,1]</code>.</li> <li>Players 0 and 2 play a game, since the skill of player 2 is higher than that of player 0, player 2 wins. The resulting queue is <code>[2,3,4,1,0]</code>.</li> <li>Players 2 and 3 play a game, since the skill of player 2 is higher than that of player 3, player 2 wins. The resulting queue is <code>[2,4,1,0,3]</code>.</li> </ul> <p>Player 2 won <code>k = 2</code> games in a row, so the winner is player 2.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">skills = [2,5,4], k = 3</span></p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong></p> <p>Initially, the queue of players is <code>[0,1,2]</code>. The following process happens:</p> <ul> <li>Players 0 and 1 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is <code>[1,2,0]</code>.</li> <li>Players 1 and 2 play a game, since the skill of player 1 is higher than that of player 2, player 1 wins. The resulting queue is <code>[1,0,2]</code>.</li> <li>Players 1 and 0 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is <code>[1,2,0]</code>.</li> </ul> <p>Player 1 won <code>k = 3</code> games in a row, so the winner is player 1.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>n == skills.length</code></li> <li><code>2 &lt;= n &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= skills[i] &lt;= 10<sup>6</sup></code></li> <li>All integers in <code>skills</code> are unique.</li> </ul>
Array; Simulation
Java
class Solution { public int findWinningPlayer(int[] skills, int k) { int n = skills.length; k = Math.min(k, n - 1); int i = 0, cnt = 0; for (int j = 1; j < n; ++j) { if (skills[i] < skills[j]) { i = j; cnt = 1; } else { ++cnt; } if (cnt == k) { break; } } return i; } }
3,175
Find The First Player to win K Games in a Row
Medium
<p>A competition consists of <code>n</code> players numbered from <code>0</code> to <code>n - 1</code>.</p> <p>You are given an integer array <code>skills</code> of size <code>n</code> and a <strong>positive</strong> integer <code>k</code>, where <code>skills[i]</code> is the skill level of player <code>i</code>. All integers in <code>skills</code> are <strong>unique</strong>.</p> <p>All players are standing in a queue in order from player <code>0</code> to player <code>n - 1</code>.</p> <p>The competition process is as follows:</p> <ul> <li>The first two players in the queue play a game, and the player with the <strong>higher</strong> skill level wins.</li> <li>After the game, the winner stays at the beginning of the queue, and the loser goes to the end of it.</li> </ul> <p>The winner of the competition is the <strong>first</strong> player who wins <code>k</code> games <strong>in a row</strong>.</p> <p>Return the initial index of the <em>winning</em> player.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">skills = [4,2,6,3,9], k = 2</span></p> <p><strong>Output:</strong> 2</p> <p><strong>Explanation:</strong></p> <p>Initially, the queue of players is <code>[0,1,2,3,4]</code>. The following process happens:</p> <ul> <li>Players 0 and 1 play a game, since the skill of player 0 is higher than that of player 1, player 0 wins. The resulting queue is <code>[0,2,3,4,1]</code>.</li> <li>Players 0 and 2 play a game, since the skill of player 2 is higher than that of player 0, player 2 wins. The resulting queue is <code>[2,3,4,1,0]</code>.</li> <li>Players 2 and 3 play a game, since the skill of player 2 is higher than that of player 3, player 2 wins. The resulting queue is <code>[2,4,1,0,3]</code>.</li> </ul> <p>Player 2 won <code>k = 2</code> games in a row, so the winner is player 2.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">skills = [2,5,4], k = 3</span></p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong></p> <p>Initially, the queue of players is <code>[0,1,2]</code>. The following process happens:</p> <ul> <li>Players 0 and 1 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is <code>[1,2,0]</code>.</li> <li>Players 1 and 2 play a game, since the skill of player 1 is higher than that of player 2, player 1 wins. The resulting queue is <code>[1,0,2]</code>.</li> <li>Players 1 and 0 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is <code>[1,2,0]</code>.</li> </ul> <p>Player 1 won <code>k = 3</code> games in a row, so the winner is player 1.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>n == skills.length</code></li> <li><code>2 &lt;= n &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= skills[i] &lt;= 10<sup>6</sup></code></li> <li>All integers in <code>skills</code> are unique.</li> </ul>
Array; Simulation
Python
class Solution: def findWinningPlayer(self, skills: List[int], k: int) -> int: n = len(skills) k = min(k, n - 1) i = cnt = 0 for j in range(1, n): if skills[i] < skills[j]: i = j cnt = 1 else: cnt += 1 if cnt == k: break return i
3,175
Find The First Player to win K Games in a Row
Medium
<p>A competition consists of <code>n</code> players numbered from <code>0</code> to <code>n - 1</code>.</p> <p>You are given an integer array <code>skills</code> of size <code>n</code> and a <strong>positive</strong> integer <code>k</code>, where <code>skills[i]</code> is the skill level of player <code>i</code>. All integers in <code>skills</code> are <strong>unique</strong>.</p> <p>All players are standing in a queue in order from player <code>0</code> to player <code>n - 1</code>.</p> <p>The competition process is as follows:</p> <ul> <li>The first two players in the queue play a game, and the player with the <strong>higher</strong> skill level wins.</li> <li>After the game, the winner stays at the beginning of the queue, and the loser goes to the end of it.</li> </ul> <p>The winner of the competition is the <strong>first</strong> player who wins <code>k</code> games <strong>in a row</strong>.</p> <p>Return the initial index of the <em>winning</em> player.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">skills = [4,2,6,3,9], k = 2</span></p> <p><strong>Output:</strong> 2</p> <p><strong>Explanation:</strong></p> <p>Initially, the queue of players is <code>[0,1,2,3,4]</code>. The following process happens:</p> <ul> <li>Players 0 and 1 play a game, since the skill of player 0 is higher than that of player 1, player 0 wins. The resulting queue is <code>[0,2,3,4,1]</code>.</li> <li>Players 0 and 2 play a game, since the skill of player 2 is higher than that of player 0, player 2 wins. The resulting queue is <code>[2,3,4,1,0]</code>.</li> <li>Players 2 and 3 play a game, since the skill of player 2 is higher than that of player 3, player 2 wins. The resulting queue is <code>[2,4,1,0,3]</code>.</li> </ul> <p>Player 2 won <code>k = 2</code> games in a row, so the winner is player 2.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">skills = [2,5,4], k = 3</span></p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong></p> <p>Initially, the queue of players is <code>[0,1,2]</code>. The following process happens:</p> <ul> <li>Players 0 and 1 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is <code>[1,2,0]</code>.</li> <li>Players 1 and 2 play a game, since the skill of player 1 is higher than that of player 2, player 1 wins. The resulting queue is <code>[1,0,2]</code>.</li> <li>Players 1 and 0 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is <code>[1,2,0]</code>.</li> </ul> <p>Player 1 won <code>k = 3</code> games in a row, so the winner is player 1.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>n == skills.length</code></li> <li><code>2 &lt;= n &lt;= 10<sup>5</sup></code></li> <li><code>1 &lt;= k &lt;= 10<sup>9</sup></code></li> <li><code>1 &lt;= skills[i] &lt;= 10<sup>6</sup></code></li> <li>All integers in <code>skills</code> are unique.</li> </ul>
Array; Simulation
TypeScript
function findWinningPlayer(skills: number[], k: number): number { const n = skills.length; k = Math.min(k, n - 1); let [i, cnt] = [0, 0]; for (let j = 1; j < n; ++j) { if (skills[i] < skills[j]) { i = j; cnt = 1; } else { ++cnt; } if (cnt === k) { break; } } return i; }
3,176
Find the Maximum Length of a Good Subsequence I
Medium
<p>You are given an integer array <code>nums</code> and a <strong>non-negative</strong> integer <code>k</code>. A sequence of integers <code>seq</code> is called <strong>good</strong> if there are <strong>at most</strong> <code>k</code> indices <code>i</code> in the range <code>[0, seq.length - 2]</code> such that <code>seq[i] != seq[i + 1]</code>.</p> <p>Return the <strong>maximum</strong> possible length of a <strong>good</strong> <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,1,1,3], k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,<u>2</u>,<u>1</u>,<u>1</u>,3]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,3,4,5,1], k = 0</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,2,3,4,5,<u>1</u>]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 500</code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>0 &lt;= k &lt;= min(nums.length, 25)</code></li> </ul>
Array; Hash Table; Dynamic Programming
C++
class Solution { public: int maximumLength(vector<int>& nums, int k) { int n = nums.size(); int f[n][k + 1]; memset(f, 0, sizeof(f)); int ans = 0; for (int i = 0; i < n; ++i) { for (int h = 0; h <= k; ++h) { for (int j = 0; j < i; ++j) { if (nums[i] == nums[j]) { f[i][h] = max(f[i][h], f[j][h]); } else if (h) { f[i][h] = max(f[i][h], f[j][h - 1]); } } ++f[i][h]; } ans = max(ans, f[i][k]); } return ans; } };
3,176
Find the Maximum Length of a Good Subsequence I
Medium
<p>You are given an integer array <code>nums</code> and a <strong>non-negative</strong> integer <code>k</code>. A sequence of integers <code>seq</code> is called <strong>good</strong> if there are <strong>at most</strong> <code>k</code> indices <code>i</code> in the range <code>[0, seq.length - 2]</code> such that <code>seq[i] != seq[i + 1]</code>.</p> <p>Return the <strong>maximum</strong> possible length of a <strong>good</strong> <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,1,1,3], k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,<u>2</u>,<u>1</u>,<u>1</u>,3]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,3,4,5,1], k = 0</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,2,3,4,5,<u>1</u>]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 500</code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>0 &lt;= k &lt;= min(nums.length, 25)</code></li> </ul>
Array; Hash Table; Dynamic Programming
Go
func maximumLength(nums []int, k int) (ans int) { f := make([][]int, len(nums)) for i := range f { f[i] = make([]int, k+1) } for i, x := range nums { for h := 0; h <= k; h++ { for j, y := range nums[:i] { if x == y { f[i][h] = max(f[i][h], f[j][h]) } else if h > 0 { f[i][h] = max(f[i][h], f[j][h-1]) } } f[i][h]++ } ans = max(ans, f[i][k]) } return }
3,176
Find the Maximum Length of a Good Subsequence I
Medium
<p>You are given an integer array <code>nums</code> and a <strong>non-negative</strong> integer <code>k</code>. A sequence of integers <code>seq</code> is called <strong>good</strong> if there are <strong>at most</strong> <code>k</code> indices <code>i</code> in the range <code>[0, seq.length - 2]</code> such that <code>seq[i] != seq[i + 1]</code>.</p> <p>Return the <strong>maximum</strong> possible length of a <strong>good</strong> <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,1,1,3], k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,<u>2</u>,<u>1</u>,<u>1</u>,3]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,3,4,5,1], k = 0</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,2,3,4,5,<u>1</u>]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 500</code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>0 &lt;= k &lt;= min(nums.length, 25)</code></li> </ul>
Array; Hash Table; Dynamic Programming
Java
class Solution { public int maximumLength(int[] nums, int k) { int n = nums.length; int[][] f = new int[n][k + 1]; int ans = 0; for (int i = 0; i < n; ++i) { for (int h = 0; h <= k; ++h) { for (int j = 0; j < i; ++j) { if (nums[i] == nums[j]) { f[i][h] = Math.max(f[i][h], f[j][h]); } else if (h > 0) { f[i][h] = Math.max(f[i][h], f[j][h - 1]); } } ++f[i][h]; } ans = Math.max(ans, f[i][k]); } return ans; } }
3,176
Find the Maximum Length of a Good Subsequence I
Medium
<p>You are given an integer array <code>nums</code> and a <strong>non-negative</strong> integer <code>k</code>. A sequence of integers <code>seq</code> is called <strong>good</strong> if there are <strong>at most</strong> <code>k</code> indices <code>i</code> in the range <code>[0, seq.length - 2]</code> such that <code>seq[i] != seq[i + 1]</code>.</p> <p>Return the <strong>maximum</strong> possible length of a <strong>good</strong> <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,1,1,3], k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,<u>2</u>,<u>1</u>,<u>1</u>,3]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,3,4,5,1], k = 0</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,2,3,4,5,<u>1</u>]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 500</code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>0 &lt;= k &lt;= min(nums.length, 25)</code></li> </ul>
Array; Hash Table; Dynamic Programming
Python
class Solution: def maximumLength(self, nums: List[int], k: int) -> int: n = len(nums) f = [[1] * (k + 1) for _ in range(n)] ans = 0 for i, x in enumerate(nums): for h in range(k + 1): for j, y in enumerate(nums[:i]): if x == y: f[i][h] = max(f[i][h], f[j][h] + 1) elif h: f[i][h] = max(f[i][h], f[j][h - 1] + 1) ans = max(ans, f[i][k]) return ans
3,176
Find the Maximum Length of a Good Subsequence I
Medium
<p>You are given an integer array <code>nums</code> and a <strong>non-negative</strong> integer <code>k</code>. A sequence of integers <code>seq</code> is called <strong>good</strong> if there are <strong>at most</strong> <code>k</code> indices <code>i</code> in the range <code>[0, seq.length - 2]</code> such that <code>seq[i] != seq[i + 1]</code>.</p> <p>Return the <strong>maximum</strong> possible length of a <strong>good</strong> <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,1,1,3], k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,<u>2</u>,<u>1</u>,<u>1</u>,3]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,3,4,5,1], k = 0</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,2,3,4,5,<u>1</u>]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 500</code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>0 &lt;= k &lt;= min(nums.length, 25)</code></li> </ul>
Array; Hash Table; Dynamic Programming
TypeScript
function maximumLength(nums: number[], k: number): number { const n = nums.length; const f: number[][] = Array.from({ length: n }, () => Array(k + 1).fill(0)); let ans = 0; for (let i = 0; i < n; ++i) { for (let h = 0; h <= k; ++h) { for (let j = 0; j < i; ++j) { if (nums[i] === nums[j]) { f[i][h] = Math.max(f[i][h], f[j][h]); } else if (h) { f[i][h] = Math.max(f[i][h], f[j][h - 1]); } } ++f[i][h]; } ans = Math.max(ans, f[i][k]); } return ans; }
3,177
Find the Maximum Length of a Good Subsequence II
Hard
<p>You are given an integer array <code>nums</code> and a <strong>non-negative</strong> integer <code>k</code>. A sequence of integers <code>seq</code> is called <strong>good</strong> if there are <strong>at most</strong> <code>k</code> indices <code>i</code> in the range <code>[0, seq.length - 2]</code> such that <code>seq[i] != seq[i + 1]</code>.</p> <p>Return the <strong>maximum</strong> possible length of a <strong>good</strong> <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,1,1,3], k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,<u>2</u>,<u>1</u>,<u>1</u>,3]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,3,4,5,1], k = 0</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,2,3,4,5,<u>1</u>]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 5 * 10<sup>3</sup></code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>0 &lt;= k &lt;= min(50, nums.length)</code></li> </ul>
Array; Hash Table; Dynamic Programming
C++
class Solution { public: int maximumLength(vector<int>& nums, int k) { int n = nums.size(); vector<vector<int>> f(n, vector<int>(k + 1)); vector<unordered_map<int, int>> mp(k + 1); vector<vector<int>> g(k + 1, vector<int>(3)); int ans = 0; for (int i = 0; i < n; ++i) { for (int h = 0; h <= k; ++h) { f[i][h] = mp[h][nums[i]]; if (h > 0) { if (g[h - 1][0] != nums[i]) { f[i][h] = max(f[i][h], g[h - 1][1]); } else { f[i][h] = max(f[i][h], g[h - 1][2]); } } ++f[i][h]; mp[h][nums[i]] = max(mp[h][nums[i]], f[i][h]); if (g[h][0] != nums[i]) { if (f[i][h] >= g[h][1]) { g[h][2] = g[h][1]; g[h][1] = f[i][h]; g[h][0] = nums[i]; } else { g[h][2] = max(g[h][2], f[i][h]); } } else { g[h][1] = max(g[h][1], f[i][h]); } ans = max(ans, f[i][h]); } } return ans; } };
3,177
Find the Maximum Length of a Good Subsequence II
Hard
<p>You are given an integer array <code>nums</code> and a <strong>non-negative</strong> integer <code>k</code>. A sequence of integers <code>seq</code> is called <strong>good</strong> if there are <strong>at most</strong> <code>k</code> indices <code>i</code> in the range <code>[0, seq.length - 2]</code> such that <code>seq[i] != seq[i + 1]</code>.</p> <p>Return the <strong>maximum</strong> possible length of a <strong>good</strong> <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,1,1,3], k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,<u>2</u>,<u>1</u>,<u>1</u>,3]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,3,4,5,1], k = 0</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,2,3,4,5,<u>1</u>]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 5 * 10<sup>3</sup></code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>0 &lt;= k &lt;= min(50, nums.length)</code></li> </ul>
Array; Hash Table; Dynamic Programming
Go
func maximumLength(nums []int, k int) int { n := len(nums) f := make([][]int, n) for i := range f { f[i] = make([]int, k+1) } mp := make([]map[int]int, k+1) for i := range mp { mp[i] = make(map[int]int) } g := make([][3]int, k+1) ans := 0 for i := 0; i < n; i++ { for h := 0; h <= k; h++ { f[i][h] = mp[h][nums[i]] if h > 0 { if g[h-1][0] != nums[i] { if g[h-1][1] > f[i][h] { f[i][h] = g[h-1][1] } } else { if g[h-1][2] > f[i][h] { f[i][h] = g[h-1][2] } } } f[i][h]++ if f[i][h] > mp[h][nums[i]] { mp[h][nums[i]] = f[i][h] } if g[h][0] != nums[i] { if f[i][h] >= g[h][1] { g[h][2] = g[h][1] g[h][1] = f[i][h] g[h][0] = nums[i] } else if f[i][h] > g[h][2] { g[h][2] = f[i][h] } } else { if f[i][h] > g[h][1] { g[h][1] = f[i][h] } } if f[i][h] > ans { ans = f[i][h] } } } return ans }
3,177
Find the Maximum Length of a Good Subsequence II
Hard
<p>You are given an integer array <code>nums</code> and a <strong>non-negative</strong> integer <code>k</code>. A sequence of integers <code>seq</code> is called <strong>good</strong> if there are <strong>at most</strong> <code>k</code> indices <code>i</code> in the range <code>[0, seq.length - 2]</code> such that <code>seq[i] != seq[i + 1]</code>.</p> <p>Return the <strong>maximum</strong> possible length of a <strong>good</strong> <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,1,1,3], k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,<u>2</u>,<u>1</u>,<u>1</u>,3]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,3,4,5,1], k = 0</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,2,3,4,5,<u>1</u>]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 5 * 10<sup>3</sup></code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>0 &lt;= k &lt;= min(50, nums.length)</code></li> </ul>
Array; Hash Table; Dynamic Programming
Java
class Solution { public int maximumLength(int[] nums, int k) { int n = nums.length; int[][] f = new int[n][k + 1]; Map<Integer, Integer>[] mp = new HashMap[k + 1]; Arrays.setAll(mp, i -> new HashMap<>()); int[][] g = new int[k + 1][3]; int ans = 0; for (int i = 0; i < n; ++i) { for (int h = 0; h <= k; ++h) { f[i][h] = mp[h].getOrDefault(nums[i], 0); if (h > 0) { if (g[h - 1][0] != nums[i]) { f[i][h] = Math.max(f[i][h], g[h - 1][1]); } else { f[i][h] = Math.max(f[i][h], g[h - 1][2]); } } ++f[i][h]; mp[h].merge(nums[i], f[i][h], Integer::max); if (g[h][0] != nums[i]) { if (f[i][h] >= g[h][1]) { g[h][2] = g[h][1]; g[h][1] = f[i][h]; g[h][0] = nums[i]; } else { g[h][2] = Math.max(g[h][2], f[i][h]); } } else { g[h][1] = Math.max(g[h][1], f[i][h]); } ans = Math.max(ans, f[i][h]); } } return ans; } }
3,177
Find the Maximum Length of a Good Subsequence II
Hard
<p>You are given an integer array <code>nums</code> and a <strong>non-negative</strong> integer <code>k</code>. A sequence of integers <code>seq</code> is called <strong>good</strong> if there are <strong>at most</strong> <code>k</code> indices <code>i</code> in the range <code>[0, seq.length - 2]</code> such that <code>seq[i] != seq[i + 1]</code>.</p> <p>Return the <strong>maximum</strong> possible length of a <strong>good</strong> <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,1,1,3], k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,<u>2</u>,<u>1</u>,<u>1</u>,3]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,3,4,5,1], k = 0</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,2,3,4,5,<u>1</u>]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 5 * 10<sup>3</sup></code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>0 &lt;= k &lt;= min(50, nums.length)</code></li> </ul>
Array; Hash Table; Dynamic Programming
Python
class Solution: def maximumLength(self, nums: List[int], k: int) -> int: n = len(nums) f = [[0] * (k + 1) for _ in range(n)] mp = [defaultdict(int) for _ in range(k + 1)] g = [[0] * 3 for _ in range(k + 1)] ans = 0 for i, x in enumerate(nums): for h in range(k + 1): f[i][h] = mp[h][x] if h: if g[h - 1][0] != nums[i]: f[i][h] = max(f[i][h], g[h - 1][1]) else: f[i][h] = max(f[i][h], g[h - 1][2]) f[i][h] += 1 mp[h][nums[i]] = max(mp[h][nums[i]], f[i][h]) if g[h][0] != x: if f[i][h] >= g[h][1]: g[h][2] = g[h][1] g[h][1] = f[i][h] g[h][0] = x else: g[h][2] = max(g[h][2], f[i][h]) else: g[h][1] = max(g[h][1], f[i][h]) ans = max(ans, f[i][h]) return ans
3,177
Find the Maximum Length of a Good Subsequence II
Hard
<p>You are given an integer array <code>nums</code> and a <strong>non-negative</strong> integer <code>k</code>. A sequence of integers <code>seq</code> is called <strong>good</strong> if there are <strong>at most</strong> <code>k</code> indices <code>i</code> in the range <code>[0, seq.length - 2]</code> such that <code>seq[i] != seq[i + 1]</code>.</p> <p>Return the <strong>maximum</strong> possible length of a <strong>good</strong> <span data-keyword="subsequence-array">subsequence</span> of <code>nums</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,1,1,3], k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,<u>2</u>,<u>1</u>,<u>1</u>,3]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">nums = [1,2,3,4,5,1], k = 0</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The maximum length subsequence is <code>[<u>1</u>,2,3,4,5,<u>1</u>]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= nums.length &lt;= 5 * 10<sup>3</sup></code></li> <li><code>1 &lt;= nums[i] &lt;= 10<sup>9</sup></code></li> <li><code>0 &lt;= k &lt;= min(50, nums.length)</code></li> </ul>
Array; Hash Table; Dynamic Programming
TypeScript
function maximumLength(nums: number[], k: number): number { const n = nums.length; const f: number[][] = Array.from({ length: n }, () => Array(k + 1).fill(0)); const mp: Map<number, number>[] = Array.from({ length: k + 1 }, () => new Map()); const g: number[][] = Array.from({ length: k + 1 }, () => Array(3).fill(0)); let ans = 0; for (let i = 0; i < n; i++) { for (let h = 0; h <= k; h++) { f[i][h] = mp[h].get(nums[i]) || 0; if (h > 0) { if (g[h - 1][0] !== nums[i]) { f[i][h] = Math.max(f[i][h], g[h - 1][1]); } else { f[i][h] = Math.max(f[i][h], g[h - 1][2]); } } f[i][h]++; mp[h].set(nums[i], Math.max(mp[h].get(nums[i]) || 0, f[i][h])); if (g[h][0] !== nums[i]) { if (f[i][h] >= g[h][1]) { g[h][2] = g[h][1]; g[h][1] = f[i][h]; g[h][0] = nums[i]; } else { g[h][2] = Math.max(g[h][2], f[i][h]); } } else { g[h][1] = Math.max(g[h][1], f[i][h]); } ans = Math.max(ans, f[i][h]); } } return ans; }
3,178
Find the Child Who Has the Ball After K Seconds
Easy
<p>You are given two <strong>positive</strong> integers <code>n</code> and <code>k</code>. There are <code>n</code> children numbered from <code>0</code> to <code>n - 1</code> standing in a queue <em>in order</em> from left to right.</p> <p>Initially, child 0 holds a ball and the direction of passing the ball is towards the right direction. After each second, the child holding the ball passes it to the child next to them. Once the ball reaches <strong>either</strong> end of the line, i.e. child 0 or child <code>n - 1</code>, the direction of passing is <strong>reversed</strong>.</p> <p>Return the number of the child who receives the ball after <code>k</code> seconds.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 3, k = 5</span></p> <p><strong>Output:</strong> <span class="example-io">1</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>]</code></td> </tr> <tr> <td><code>3</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> <tr> <td><code>4</code></td> <td><code>[<u>0</u>, 1, 2]</code></td> </tr> <tr> <td><code>5</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> </tbody> </table> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5, k = 6</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2, 3, 4]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2, 3, 4]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>, 3, 4]</code></td> </tr> <tr> <td><code>3</code></td> <td><code>[0, 1, 2, <u>3</u>, 4]</code></td> </tr> <tr> <td><code>4</code></td> <td><code>[0, 1, 2, 3, <u>4</u>]</code></td> </tr> <tr> <td><code>5</code></td> <td><code>[0, 1, 2, <u>3</u>, 4]</code></td> </tr> <tr> <td><code>6</code></td> <td><code>[0, 1, <u>2</u>, 3, 4]</code></td> </tr> </tbody> </table> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4, k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2, 3]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2, 3]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>, 3]</code></td> </tr> </tbody> </table> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 &lt;= n &lt;= 50</code></li> <li><code>1 &lt;= k &lt;= 50</code></li> </ul> <p>&nbsp;</p> <p><strong>Note:</strong> This question is the same as <a href="https://leetcode.com/problems/pass-the-pillow/description/" target="_blank"> 2582: Pass the Pillow.</a></p>
Math; Simulation
C++
class Solution { public: int numberOfChild(int n, int k) { int mod = k % (n - 1); k /= (n - 1); return k % 2 == 1 ? n - mod - 1 : mod; } };
3,178
Find the Child Who Has the Ball After K Seconds
Easy
<p>You are given two <strong>positive</strong> integers <code>n</code> and <code>k</code>. There are <code>n</code> children numbered from <code>0</code> to <code>n - 1</code> standing in a queue <em>in order</em> from left to right.</p> <p>Initially, child 0 holds a ball and the direction of passing the ball is towards the right direction. After each second, the child holding the ball passes it to the child next to them. Once the ball reaches <strong>either</strong> end of the line, i.e. child 0 or child <code>n - 1</code>, the direction of passing is <strong>reversed</strong>.</p> <p>Return the number of the child who receives the ball after <code>k</code> seconds.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 3, k = 5</span></p> <p><strong>Output:</strong> <span class="example-io">1</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>]</code></td> </tr> <tr> <td><code>3</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> <tr> <td><code>4</code></td> <td><code>[<u>0</u>, 1, 2]</code></td> </tr> <tr> <td><code>5</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> </tbody> </table> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5, k = 6</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2, 3, 4]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2, 3, 4]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>, 3, 4]</code></td> </tr> <tr> <td><code>3</code></td> <td><code>[0, 1, 2, <u>3</u>, 4]</code></td> </tr> <tr> <td><code>4</code></td> <td><code>[0, 1, 2, 3, <u>4</u>]</code></td> </tr> <tr> <td><code>5</code></td> <td><code>[0, 1, 2, <u>3</u>, 4]</code></td> </tr> <tr> <td><code>6</code></td> <td><code>[0, 1, <u>2</u>, 3, 4]</code></td> </tr> </tbody> </table> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4, k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2, 3]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2, 3]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>, 3]</code></td> </tr> </tbody> </table> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 &lt;= n &lt;= 50</code></li> <li><code>1 &lt;= k &lt;= 50</code></li> </ul> <p>&nbsp;</p> <p><strong>Note:</strong> This question is the same as <a href="https://leetcode.com/problems/pass-the-pillow/description/" target="_blank"> 2582: Pass the Pillow.</a></p>
Math; Simulation
Go
func numberOfChild(n int, k int) int { mod := k % (n - 1) k /= (n - 1) if k%2 == 1 { return n - mod - 1 } return mod }
3,178
Find the Child Who Has the Ball After K Seconds
Easy
<p>You are given two <strong>positive</strong> integers <code>n</code> and <code>k</code>. There are <code>n</code> children numbered from <code>0</code> to <code>n - 1</code> standing in a queue <em>in order</em> from left to right.</p> <p>Initially, child 0 holds a ball and the direction of passing the ball is towards the right direction. After each second, the child holding the ball passes it to the child next to them. Once the ball reaches <strong>either</strong> end of the line, i.e. child 0 or child <code>n - 1</code>, the direction of passing is <strong>reversed</strong>.</p> <p>Return the number of the child who receives the ball after <code>k</code> seconds.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 3, k = 5</span></p> <p><strong>Output:</strong> <span class="example-io">1</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>]</code></td> </tr> <tr> <td><code>3</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> <tr> <td><code>4</code></td> <td><code>[<u>0</u>, 1, 2]</code></td> </tr> <tr> <td><code>5</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> </tbody> </table> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5, k = 6</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2, 3, 4]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2, 3, 4]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>, 3, 4]</code></td> </tr> <tr> <td><code>3</code></td> <td><code>[0, 1, 2, <u>3</u>, 4]</code></td> </tr> <tr> <td><code>4</code></td> <td><code>[0, 1, 2, 3, <u>4</u>]</code></td> </tr> <tr> <td><code>5</code></td> <td><code>[0, 1, 2, <u>3</u>, 4]</code></td> </tr> <tr> <td><code>6</code></td> <td><code>[0, 1, <u>2</u>, 3, 4]</code></td> </tr> </tbody> </table> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4, k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2, 3]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2, 3]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>, 3]</code></td> </tr> </tbody> </table> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 &lt;= n &lt;= 50</code></li> <li><code>1 &lt;= k &lt;= 50</code></li> </ul> <p>&nbsp;</p> <p><strong>Note:</strong> This question is the same as <a href="https://leetcode.com/problems/pass-the-pillow/description/" target="_blank"> 2582: Pass the Pillow.</a></p>
Math; Simulation
Java
class Solution { public int numberOfChild(int n, int k) { int mod = k % (n - 1); k /= (n - 1); return k % 2 == 1 ? n - mod - 1 : mod; } }
3,178
Find the Child Who Has the Ball After K Seconds
Easy
<p>You are given two <strong>positive</strong> integers <code>n</code> and <code>k</code>. There are <code>n</code> children numbered from <code>0</code> to <code>n - 1</code> standing in a queue <em>in order</em> from left to right.</p> <p>Initially, child 0 holds a ball and the direction of passing the ball is towards the right direction. After each second, the child holding the ball passes it to the child next to them. Once the ball reaches <strong>either</strong> end of the line, i.e. child 0 or child <code>n - 1</code>, the direction of passing is <strong>reversed</strong>.</p> <p>Return the number of the child who receives the ball after <code>k</code> seconds.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 3, k = 5</span></p> <p><strong>Output:</strong> <span class="example-io">1</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>]</code></td> </tr> <tr> <td><code>3</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> <tr> <td><code>4</code></td> <td><code>[<u>0</u>, 1, 2]</code></td> </tr> <tr> <td><code>5</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> </tbody> </table> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5, k = 6</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2, 3, 4]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2, 3, 4]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>, 3, 4]</code></td> </tr> <tr> <td><code>3</code></td> <td><code>[0, 1, 2, <u>3</u>, 4]</code></td> </tr> <tr> <td><code>4</code></td> <td><code>[0, 1, 2, 3, <u>4</u>]</code></td> </tr> <tr> <td><code>5</code></td> <td><code>[0, 1, 2, <u>3</u>, 4]</code></td> </tr> <tr> <td><code>6</code></td> <td><code>[0, 1, <u>2</u>, 3, 4]</code></td> </tr> </tbody> </table> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4, k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2, 3]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2, 3]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>, 3]</code></td> </tr> </tbody> </table> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 &lt;= n &lt;= 50</code></li> <li><code>1 &lt;= k &lt;= 50</code></li> </ul> <p>&nbsp;</p> <p><strong>Note:</strong> This question is the same as <a href="https://leetcode.com/problems/pass-the-pillow/description/" target="_blank"> 2582: Pass the Pillow.</a></p>
Math; Simulation
Python
class Solution: def numberOfChild(self, n: int, k: int) -> int: k, mod = divmod(k, n - 1) return n - mod - 1 if k & 1 else mod
3,178
Find the Child Who Has the Ball After K Seconds
Easy
<p>You are given two <strong>positive</strong> integers <code>n</code> and <code>k</code>. There are <code>n</code> children numbered from <code>0</code> to <code>n - 1</code> standing in a queue <em>in order</em> from left to right.</p> <p>Initially, child 0 holds a ball and the direction of passing the ball is towards the right direction. After each second, the child holding the ball passes it to the child next to them. Once the ball reaches <strong>either</strong> end of the line, i.e. child 0 or child <code>n - 1</code>, the direction of passing is <strong>reversed</strong>.</p> <p>Return the number of the child who receives the ball after <code>k</code> seconds.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 3, k = 5</span></p> <p><strong>Output:</strong> <span class="example-io">1</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>]</code></td> </tr> <tr> <td><code>3</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> <tr> <td><code>4</code></td> <td><code>[<u>0</u>, 1, 2]</code></td> </tr> <tr> <td><code>5</code></td> <td><code>[0, <u>1</u>, 2]</code></td> </tr> </tbody> </table> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5, k = 6</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2, 3, 4]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2, 3, 4]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>, 3, 4]</code></td> </tr> <tr> <td><code>3</code></td> <td><code>[0, 1, 2, <u>3</u>, 4]</code></td> </tr> <tr> <td><code>4</code></td> <td><code>[0, 1, 2, 3, <u>4</u>]</code></td> </tr> <tr> <td><code>5</code></td> <td><code>[0, 1, 2, <u>3</u>, 4]</code></td> </tr> <tr> <td><code>6</code></td> <td><code>[0, 1, <u>2</u>, 3, 4]</code></td> </tr> </tbody> </table> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4, k = 2</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <table> <tbody> <tr> <th>Time elapsed</th> <th>Children</th> </tr> <tr> <td><code>0</code></td> <td><code>[<u>0</u>, 1, 2, 3]</code></td> </tr> <tr> <td><code>1</code></td> <td><code>[0, <u>1</u>, 2, 3]</code></td> </tr> <tr> <td><code>2</code></td> <td><code>[0, 1, <u>2</u>, 3]</code></td> </tr> </tbody> </table> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 &lt;= n &lt;= 50</code></li> <li><code>1 &lt;= k &lt;= 50</code></li> </ul> <p>&nbsp;</p> <p><strong>Note:</strong> This question is the same as <a href="https://leetcode.com/problems/pass-the-pillow/description/" target="_blank"> 2582: Pass the Pillow.</a></p>
Math; Simulation
TypeScript
function numberOfChild(n: number, k: number): number { const mod = k % (n - 1); k = (k / (n - 1)) | 0; return k % 2 ? n - mod - 1 : mod; }
3,179
Find the N-th Value After K Seconds
Medium
<p>You are given two integers <code>n</code> and <code>k</code>.</p> <p>Initially, you start with an array <code>a</code> of <code>n</code> integers where <code>a[i] = 1</code> for all <code>0 &lt;= i &lt;= n - 1</code>. After each second, you simultaneously update each element to be the sum of all its preceding elements plus the element itself. For example, after one second, <code>a[0]</code> remains the same, <code>a[1]</code> becomes <code>a[0] + a[1]</code>, <code>a[2]</code> becomes <code>a[0] + a[1] + a[2]</code>, and so on.</p> <p>Return the <strong>value</strong> of <code>a[n - 1]</code> after <code>k</code> seconds.</p> <p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4, k = 5</span></p> <p><strong>Output:</strong> <span class="example-io">56</span></p> <p><strong>Explanation:</strong></p> <table border="1"> <tbody> <tr> <th>Second</th> <th>State After</th> </tr> <tr> <td>0</td> <td>[1,1,1,1]</td> </tr> <tr> <td>1</td> <td>[1,2,3,4]</td> </tr> <tr> <td>2</td> <td>[1,3,6,10]</td> </tr> <tr> <td>3</td> <td>[1,4,10,20]</td> </tr> <tr> <td>4</td> <td>[1,5,15,35]</td> </tr> <tr> <td>5</td> <td>[1,6,21,56]</td> </tr> </tbody> </table> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5, k = 3</span></p> <p><strong>Output:</strong> <span class="example-io">35</span></p> <p><strong>Explanation:</strong></p> <table border="1"> <tbody> <tr> <th>Second</th> <th>State After</th> </tr> <tr> <td>0</td> <td>[1,1,1,1,1]</td> </tr> <tr> <td>1</td> <td>[1,2,3,4,5]</td> </tr> <tr> <td>2</td> <td>[1,3,6,10,15]</td> </tr> <tr> <td>3</td> <td>[1,4,10,20,35]</td> </tr> </tbody> </table> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n, k &lt;= 1000</code></li> </ul>
Array; Math; Combinatorics; Prefix Sum; Simulation
C++
class Solution { public: int valueAfterKSeconds(int n, int k) { const int mod = 1e9 + 7; vector<int> a(n, 1); while (k-- > 0) { for (int i = 1; i < n; ++i) { a[i] = (a[i] + a[i - 1]) % mod; } } return a[n - 1]; } };
3,179
Find the N-th Value After K Seconds
Medium
<p>You are given two integers <code>n</code> and <code>k</code>.</p> <p>Initially, you start with an array <code>a</code> of <code>n</code> integers where <code>a[i] = 1</code> for all <code>0 &lt;= i &lt;= n - 1</code>. After each second, you simultaneously update each element to be the sum of all its preceding elements plus the element itself. For example, after one second, <code>a[0]</code> remains the same, <code>a[1]</code> becomes <code>a[0] + a[1]</code>, <code>a[2]</code> becomes <code>a[0] + a[1] + a[2]</code>, and so on.</p> <p>Return the <strong>value</strong> of <code>a[n - 1]</code> after <code>k</code> seconds.</p> <p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4, k = 5</span></p> <p><strong>Output:</strong> <span class="example-io">56</span></p> <p><strong>Explanation:</strong></p> <table border="1"> <tbody> <tr> <th>Second</th> <th>State After</th> </tr> <tr> <td>0</td> <td>[1,1,1,1]</td> </tr> <tr> <td>1</td> <td>[1,2,3,4]</td> </tr> <tr> <td>2</td> <td>[1,3,6,10]</td> </tr> <tr> <td>3</td> <td>[1,4,10,20]</td> </tr> <tr> <td>4</td> <td>[1,5,15,35]</td> </tr> <tr> <td>5</td> <td>[1,6,21,56]</td> </tr> </tbody> </table> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5, k = 3</span></p> <p><strong>Output:</strong> <span class="example-io">35</span></p> <p><strong>Explanation:</strong></p> <table border="1"> <tbody> <tr> <th>Second</th> <th>State After</th> </tr> <tr> <td>0</td> <td>[1,1,1,1,1]</td> </tr> <tr> <td>1</td> <td>[1,2,3,4,5]</td> </tr> <tr> <td>2</td> <td>[1,3,6,10,15]</td> </tr> <tr> <td>3</td> <td>[1,4,10,20,35]</td> </tr> </tbody> </table> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n, k &lt;= 1000</code></li> </ul>
Array; Math; Combinatorics; Prefix Sum; Simulation
Go
func valueAfterKSeconds(n int, k int) int { const mod int = 1e9 + 7 a := make([]int, n) for i := range a { a[i] = 1 } for ; k > 0; k-- { for i := 1; i < n; i++ { a[i] = (a[i] + a[i-1]) % mod } } return a[n-1] }
3,179
Find the N-th Value After K Seconds
Medium
<p>You are given two integers <code>n</code> and <code>k</code>.</p> <p>Initially, you start with an array <code>a</code> of <code>n</code> integers where <code>a[i] = 1</code> for all <code>0 &lt;= i &lt;= n - 1</code>. After each second, you simultaneously update each element to be the sum of all its preceding elements plus the element itself. For example, after one second, <code>a[0]</code> remains the same, <code>a[1]</code> becomes <code>a[0] + a[1]</code>, <code>a[2]</code> becomes <code>a[0] + a[1] + a[2]</code>, and so on.</p> <p>Return the <strong>value</strong> of <code>a[n - 1]</code> after <code>k</code> seconds.</p> <p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4, k = 5</span></p> <p><strong>Output:</strong> <span class="example-io">56</span></p> <p><strong>Explanation:</strong></p> <table border="1"> <tbody> <tr> <th>Second</th> <th>State After</th> </tr> <tr> <td>0</td> <td>[1,1,1,1]</td> </tr> <tr> <td>1</td> <td>[1,2,3,4]</td> </tr> <tr> <td>2</td> <td>[1,3,6,10]</td> </tr> <tr> <td>3</td> <td>[1,4,10,20]</td> </tr> <tr> <td>4</td> <td>[1,5,15,35]</td> </tr> <tr> <td>5</td> <td>[1,6,21,56]</td> </tr> </tbody> </table> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5, k = 3</span></p> <p><strong>Output:</strong> <span class="example-io">35</span></p> <p><strong>Explanation:</strong></p> <table border="1"> <tbody> <tr> <th>Second</th> <th>State After</th> </tr> <tr> <td>0</td> <td>[1,1,1,1,1]</td> </tr> <tr> <td>1</td> <td>[1,2,3,4,5]</td> </tr> <tr> <td>2</td> <td>[1,3,6,10,15]</td> </tr> <tr> <td>3</td> <td>[1,4,10,20,35]</td> </tr> </tbody> </table> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n, k &lt;= 1000</code></li> </ul>
Array; Math; Combinatorics; Prefix Sum; Simulation
Java
class Solution { public int valueAfterKSeconds(int n, int k) { final int mod = (int) 1e9 + 7; int[] a = new int[n]; Arrays.fill(a, 1); while (k-- > 0) { for (int i = 1; i < n; ++i) { a[i] = (a[i] + a[i - 1]) % mod; } } return a[n - 1]; } }
3,179
Find the N-th Value After K Seconds
Medium
<p>You are given two integers <code>n</code> and <code>k</code>.</p> <p>Initially, you start with an array <code>a</code> of <code>n</code> integers where <code>a[i] = 1</code> for all <code>0 &lt;= i &lt;= n - 1</code>. After each second, you simultaneously update each element to be the sum of all its preceding elements plus the element itself. For example, after one second, <code>a[0]</code> remains the same, <code>a[1]</code> becomes <code>a[0] + a[1]</code>, <code>a[2]</code> becomes <code>a[0] + a[1] + a[2]</code>, and so on.</p> <p>Return the <strong>value</strong> of <code>a[n - 1]</code> after <code>k</code> seconds.</p> <p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4, k = 5</span></p> <p><strong>Output:</strong> <span class="example-io">56</span></p> <p><strong>Explanation:</strong></p> <table border="1"> <tbody> <tr> <th>Second</th> <th>State After</th> </tr> <tr> <td>0</td> <td>[1,1,1,1]</td> </tr> <tr> <td>1</td> <td>[1,2,3,4]</td> </tr> <tr> <td>2</td> <td>[1,3,6,10]</td> </tr> <tr> <td>3</td> <td>[1,4,10,20]</td> </tr> <tr> <td>4</td> <td>[1,5,15,35]</td> </tr> <tr> <td>5</td> <td>[1,6,21,56]</td> </tr> </tbody> </table> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5, k = 3</span></p> <p><strong>Output:</strong> <span class="example-io">35</span></p> <p><strong>Explanation:</strong></p> <table border="1"> <tbody> <tr> <th>Second</th> <th>State After</th> </tr> <tr> <td>0</td> <td>[1,1,1,1,1]</td> </tr> <tr> <td>1</td> <td>[1,2,3,4,5]</td> </tr> <tr> <td>2</td> <td>[1,3,6,10,15]</td> </tr> <tr> <td>3</td> <td>[1,4,10,20,35]</td> </tr> </tbody> </table> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n, k &lt;= 1000</code></li> </ul>
Array; Math; Combinatorics; Prefix Sum; Simulation
Python
class Solution: def valueAfterKSeconds(self, n: int, k: int) -> int: a = [1] * n mod = 10**9 + 7 for _ in range(k): for i in range(1, n): a[i] = (a[i] + a[i - 1]) % mod return a[n - 1]
3,179
Find the N-th Value After K Seconds
Medium
<p>You are given two integers <code>n</code> and <code>k</code>.</p> <p>Initially, you start with an array <code>a</code> of <code>n</code> integers where <code>a[i] = 1</code> for all <code>0 &lt;= i &lt;= n - 1</code>. After each second, you simultaneously update each element to be the sum of all its preceding elements plus the element itself. For example, after one second, <code>a[0]</code> remains the same, <code>a[1]</code> becomes <code>a[0] + a[1]</code>, <code>a[2]</code> becomes <code>a[0] + a[1] + a[2]</code>, and so on.</p> <p>Return the <strong>value</strong> of <code>a[n - 1]</code> after <code>k</code> seconds.</p> <p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4, k = 5</span></p> <p><strong>Output:</strong> <span class="example-io">56</span></p> <p><strong>Explanation:</strong></p> <table border="1"> <tbody> <tr> <th>Second</th> <th>State After</th> </tr> <tr> <td>0</td> <td>[1,1,1,1]</td> </tr> <tr> <td>1</td> <td>[1,2,3,4]</td> </tr> <tr> <td>2</td> <td>[1,3,6,10]</td> </tr> <tr> <td>3</td> <td>[1,4,10,20]</td> </tr> <tr> <td>4</td> <td>[1,5,15,35]</td> </tr> <tr> <td>5</td> <td>[1,6,21,56]</td> </tr> </tbody> </table> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5, k = 3</span></p> <p><strong>Output:</strong> <span class="example-io">35</span></p> <p><strong>Explanation:</strong></p> <table border="1"> <tbody> <tr> <th>Second</th> <th>State After</th> </tr> <tr> <td>0</td> <td>[1,1,1,1,1]</td> </tr> <tr> <td>1</td> <td>[1,2,3,4,5]</td> </tr> <tr> <td>2</td> <td>[1,3,6,10,15]</td> </tr> <tr> <td>3</td> <td>[1,4,10,20,35]</td> </tr> </tbody> </table> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n, k &lt;= 1000</code></li> </ul>
Array; Math; Combinatorics; Prefix Sum; Simulation
TypeScript
function valueAfterKSeconds(n: number, k: number): number { const a: number[] = Array(n).fill(1); const mod: number = 10 ** 9 + 7; while (k--) { for (let i = 1; i < n; ++i) { a[i] = (a[i] + a[i - 1]) % mod; } } return a[n - 1]; }
3,180
Maximum Total Reward Using Operations I
Medium
<p>You are given an integer array <code>rewardValues</code> of length <code>n</code>, representing the values of rewards.</p> <p>Initially, your total reward <code>x</code> is 0, and all indices are <strong>unmarked</strong>. You are allowed to perform the following operation <strong>any</strong> number of times:</p> <ul> <li>Choose an <strong>unmarked</strong> index <code>i</code> from the range <code>[0, n - 1]</code>.</li> <li>If <code>rewardValues[i]</code> is <strong>greater</strong> than your current total reward <code>x</code>, then add <code>rewardValues[i]</code> to <code>x</code> (i.e., <code>x = x + rewardValues[i]</code>), and <strong>mark</strong> the index <code>i</code>.</li> </ul> <p>Return an integer denoting the <strong>maximum </strong><em>total reward</em> you can collect by performing the operations optimally.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,1,3,3]</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>During the operations, we can choose to mark the indices 0 and 2 in order, and the total reward will be 4, which is the maximum.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,6,4,3,2]</span></p> <p><strong>Output:</strong> <span class="example-io">11</span></p> <p><strong>Explanation:</strong></p> <p>Mark the indices 0, 2, and 1 in order. The total reward will then be 11, which is the maximum.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= rewardValues.length &lt;= 2000</code></li> <li><code>1 &lt;= rewardValues[i] &lt;= 2000</code></li> </ul>
Array; Dynamic Programming
C++
class Solution { public: int maxTotalReward(vector<int>& rewardValues) { sort(rewardValues.begin(), rewardValues.end()); int n = rewardValues.size(); int f[rewardValues.back() << 1]; memset(f, -1, sizeof(f)); function<int(int)> dfs = [&](int x) { if (f[x] != -1) { return f[x]; } auto it = upper_bound(rewardValues.begin(), rewardValues.end(), x); int ans = 0; for (; it != rewardValues.end(); ++it) { ans = max(ans, rewardValues[it - rewardValues.begin()] + dfs(x + *it)); } return f[x] = ans; }; return dfs(0); } };
3,180
Maximum Total Reward Using Operations I
Medium
<p>You are given an integer array <code>rewardValues</code> of length <code>n</code>, representing the values of rewards.</p> <p>Initially, your total reward <code>x</code> is 0, and all indices are <strong>unmarked</strong>. You are allowed to perform the following operation <strong>any</strong> number of times:</p> <ul> <li>Choose an <strong>unmarked</strong> index <code>i</code> from the range <code>[0, n - 1]</code>.</li> <li>If <code>rewardValues[i]</code> is <strong>greater</strong> than your current total reward <code>x</code>, then add <code>rewardValues[i]</code> to <code>x</code> (i.e., <code>x = x + rewardValues[i]</code>), and <strong>mark</strong> the index <code>i</code>.</li> </ul> <p>Return an integer denoting the <strong>maximum </strong><em>total reward</em> you can collect by performing the operations optimally.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,1,3,3]</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>During the operations, we can choose to mark the indices 0 and 2 in order, and the total reward will be 4, which is the maximum.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,6,4,3,2]</span></p> <p><strong>Output:</strong> <span class="example-io">11</span></p> <p><strong>Explanation:</strong></p> <p>Mark the indices 0, 2, and 1 in order. The total reward will then be 11, which is the maximum.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= rewardValues.length &lt;= 2000</code></li> <li><code>1 &lt;= rewardValues[i] &lt;= 2000</code></li> </ul>
Array; Dynamic Programming
Go
func maxTotalReward(rewardValues []int) int { sort.Ints(rewardValues) n := len(rewardValues) f := make([]int, rewardValues[n-1]<<1) for i := range f { f[i] = -1 } var dfs func(int) int dfs = func(x int) int { if f[x] != -1 { return f[x] } i := sort.SearchInts(rewardValues, x+1) f[x] = 0 for _, v := range rewardValues[i:] { f[x] = max(f[x], v+dfs(x+v)) } return f[x] } return dfs(0) }
3,180
Maximum Total Reward Using Operations I
Medium
<p>You are given an integer array <code>rewardValues</code> of length <code>n</code>, representing the values of rewards.</p> <p>Initially, your total reward <code>x</code> is 0, and all indices are <strong>unmarked</strong>. You are allowed to perform the following operation <strong>any</strong> number of times:</p> <ul> <li>Choose an <strong>unmarked</strong> index <code>i</code> from the range <code>[0, n - 1]</code>.</li> <li>If <code>rewardValues[i]</code> is <strong>greater</strong> than your current total reward <code>x</code>, then add <code>rewardValues[i]</code> to <code>x</code> (i.e., <code>x = x + rewardValues[i]</code>), and <strong>mark</strong> the index <code>i</code>.</li> </ul> <p>Return an integer denoting the <strong>maximum </strong><em>total reward</em> you can collect by performing the operations optimally.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,1,3,3]</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>During the operations, we can choose to mark the indices 0 and 2 in order, and the total reward will be 4, which is the maximum.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,6,4,3,2]</span></p> <p><strong>Output:</strong> <span class="example-io">11</span></p> <p><strong>Explanation:</strong></p> <p>Mark the indices 0, 2, and 1 in order. The total reward will then be 11, which is the maximum.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= rewardValues.length &lt;= 2000</code></li> <li><code>1 &lt;= rewardValues[i] &lt;= 2000</code></li> </ul>
Array; Dynamic Programming
Java
class Solution { private int[] nums; private Integer[] f; public int maxTotalReward(int[] rewardValues) { nums = rewardValues; Arrays.sort(nums); int n = nums.length; f = new Integer[nums[n - 1] << 1]; return dfs(0); } private int dfs(int x) { if (f[x] != null) { return f[x]; } int i = Arrays.binarySearch(nums, x + 1); i = i < 0 ? -i - 1 : i; int ans = 0; for (; i < nums.length; ++i) { ans = Math.max(ans, nums[i] + dfs(x + nums[i])); } return f[x] = ans; } }
3,180
Maximum Total Reward Using Operations I
Medium
<p>You are given an integer array <code>rewardValues</code> of length <code>n</code>, representing the values of rewards.</p> <p>Initially, your total reward <code>x</code> is 0, and all indices are <strong>unmarked</strong>. You are allowed to perform the following operation <strong>any</strong> number of times:</p> <ul> <li>Choose an <strong>unmarked</strong> index <code>i</code> from the range <code>[0, n - 1]</code>.</li> <li>If <code>rewardValues[i]</code> is <strong>greater</strong> than your current total reward <code>x</code>, then add <code>rewardValues[i]</code> to <code>x</code> (i.e., <code>x = x + rewardValues[i]</code>), and <strong>mark</strong> the index <code>i</code>.</li> </ul> <p>Return an integer denoting the <strong>maximum </strong><em>total reward</em> you can collect by performing the operations optimally.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,1,3,3]</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>During the operations, we can choose to mark the indices 0 and 2 in order, and the total reward will be 4, which is the maximum.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,6,4,3,2]</span></p> <p><strong>Output:</strong> <span class="example-io">11</span></p> <p><strong>Explanation:</strong></p> <p>Mark the indices 0, 2, and 1 in order. The total reward will then be 11, which is the maximum.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= rewardValues.length &lt;= 2000</code></li> <li><code>1 &lt;= rewardValues[i] &lt;= 2000</code></li> </ul>
Array; Dynamic Programming
Python
class Solution: def maxTotalReward(self, rewardValues: List[int]) -> int: @cache def dfs(x: int) -> int: i = bisect_right(rewardValues, x) ans = 0 for v in rewardValues[i:]: ans = max(ans, v + dfs(x + v)) return ans rewardValues.sort() return dfs(0)
3,180
Maximum Total Reward Using Operations I
Medium
<p>You are given an integer array <code>rewardValues</code> of length <code>n</code>, representing the values of rewards.</p> <p>Initially, your total reward <code>x</code> is 0, and all indices are <strong>unmarked</strong>. You are allowed to perform the following operation <strong>any</strong> number of times:</p> <ul> <li>Choose an <strong>unmarked</strong> index <code>i</code> from the range <code>[0, n - 1]</code>.</li> <li>If <code>rewardValues[i]</code> is <strong>greater</strong> than your current total reward <code>x</code>, then add <code>rewardValues[i]</code> to <code>x</code> (i.e., <code>x = x + rewardValues[i]</code>), and <strong>mark</strong> the index <code>i</code>.</li> </ul> <p>Return an integer denoting the <strong>maximum </strong><em>total reward</em> you can collect by performing the operations optimally.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,1,3,3]</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>During the operations, we can choose to mark the indices 0 and 2 in order, and the total reward will be 4, which is the maximum.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,6,4,3,2]</span></p> <p><strong>Output:</strong> <span class="example-io">11</span></p> <p><strong>Explanation:</strong></p> <p>Mark the indices 0, 2, and 1 in order. The total reward will then be 11, which is the maximum.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= rewardValues.length &lt;= 2000</code></li> <li><code>1 &lt;= rewardValues[i] &lt;= 2000</code></li> </ul>
Array; Dynamic Programming
TypeScript
function maxTotalReward(rewardValues: number[]): number { rewardValues.sort((a, b) => a - b); const search = (x: number): number => { let [l, r] = [0, rewardValues.length]; while (l < r) { const mid = (l + r) >> 1; if (rewardValues[mid] > x) { r = mid; } else { l = mid + 1; } } return l; }; const f: number[] = Array(rewardValues.at(-1)! << 1).fill(-1); const dfs = (x: number): number => { if (f[x] !== -1) { return f[x]; } let ans = 0; for (let i = search(x); i < rewardValues.length; ++i) { ans = Math.max(ans, rewardValues[i] + dfs(x + rewardValues[i])); } return (f[x] = ans); }; return dfs(0); }
3,181
Maximum Total Reward Using Operations II
Hard
<p>You are given an integer array <code>rewardValues</code> of length <code>n</code>, representing the values of rewards.</p> <p>Initially, your total reward <code>x</code> is 0, and all indices are <strong>unmarked</strong>. You are allowed to perform the following operation <strong>any</strong> number of times:</p> <ul> <li>Choose an <strong>unmarked</strong> index <code>i</code> from the range <code>[0, n - 1]</code>.</li> <li>If <code>rewardValues[i]</code> is <strong>greater</strong> than your current total reward <code>x</code>, then add <code>rewardValues[i]</code> to <code>x</code> (i.e., <code>x = x + rewardValues[i]</code>), and <strong>mark</strong> the index <code>i</code>.</li> </ul> <p>Return an integer denoting the <strong>maximum </strong><em>total reward</em> you can collect by performing the operations optimally.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,1,3,3]</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>During the operations, we can choose to mark the indices 0 and 2 in order, and the total reward will be 4, which is the maximum.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,6,4,3,2]</span></p> <p><strong>Output:</strong> <span class="example-io">11</span></p> <p><strong>Explanation:</strong></p> <p>Mark the indices 0, 2, and 1 in order. The total reward will then be 11, which is the maximum.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= rewardValues.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>1 &lt;= rewardValues[i] &lt;= 5 * 10<sup>4</sup></code></li> </ul>
Bit Manipulation; Array; Dynamic Programming
C++
class Solution { public: int maxTotalReward(vector<int>& rewardValues) { sort(rewardValues.begin(), rewardValues.end()); rewardValues.erase(unique(rewardValues.begin(), rewardValues.end()), rewardValues.end()); bitset<100000> f{1}; for (int v : rewardValues) { int shift = f.size() - v; f |= f << shift >> (shift - v); } for (int i = rewardValues.back() * 2 - 1;; i--) { if (f.test(i)) { return i; } } } };
3,181
Maximum Total Reward Using Operations II
Hard
<p>You are given an integer array <code>rewardValues</code> of length <code>n</code>, representing the values of rewards.</p> <p>Initially, your total reward <code>x</code> is 0, and all indices are <strong>unmarked</strong>. You are allowed to perform the following operation <strong>any</strong> number of times:</p> <ul> <li>Choose an <strong>unmarked</strong> index <code>i</code> from the range <code>[0, n - 1]</code>.</li> <li>If <code>rewardValues[i]</code> is <strong>greater</strong> than your current total reward <code>x</code>, then add <code>rewardValues[i]</code> to <code>x</code> (i.e., <code>x = x + rewardValues[i]</code>), and <strong>mark</strong> the index <code>i</code>.</li> </ul> <p>Return an integer denoting the <strong>maximum </strong><em>total reward</em> you can collect by performing the operations optimally.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,1,3,3]</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>During the operations, we can choose to mark the indices 0 and 2 in order, and the total reward will be 4, which is the maximum.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,6,4,3,2]</span></p> <p><strong>Output:</strong> <span class="example-io">11</span></p> <p><strong>Explanation:</strong></p> <p>Mark the indices 0, 2, and 1 in order. The total reward will then be 11, which is the maximum.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= rewardValues.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>1 &lt;= rewardValues[i] &lt;= 5 * 10<sup>4</sup></code></li> </ul>
Bit Manipulation; Array; Dynamic Programming
Go
func maxTotalReward(rewardValues []int) int { slices.Sort(rewardValues) rewardValues = slices.Compact(rewardValues) one := big.NewInt(1) f := big.NewInt(1) p := new(big.Int) for _, v := range rewardValues { mask := p.Sub(p.Lsh(one, uint(v)), one) f.Or(f, p.Lsh(p.And(f, mask), uint(v))) } return f.BitLen() - 1 }
3,181
Maximum Total Reward Using Operations II
Hard
<p>You are given an integer array <code>rewardValues</code> of length <code>n</code>, representing the values of rewards.</p> <p>Initially, your total reward <code>x</code> is 0, and all indices are <strong>unmarked</strong>. You are allowed to perform the following operation <strong>any</strong> number of times:</p> <ul> <li>Choose an <strong>unmarked</strong> index <code>i</code> from the range <code>[0, n - 1]</code>.</li> <li>If <code>rewardValues[i]</code> is <strong>greater</strong> than your current total reward <code>x</code>, then add <code>rewardValues[i]</code> to <code>x</code> (i.e., <code>x = x + rewardValues[i]</code>), and <strong>mark</strong> the index <code>i</code>.</li> </ul> <p>Return an integer denoting the <strong>maximum </strong><em>total reward</em> you can collect by performing the operations optimally.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,1,3,3]</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>During the operations, we can choose to mark the indices 0 and 2 in order, and the total reward will be 4, which is the maximum.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,6,4,3,2]</span></p> <p><strong>Output:</strong> <span class="example-io">11</span></p> <p><strong>Explanation:</strong></p> <p>Mark the indices 0, 2, and 1 in order. The total reward will then be 11, which is the maximum.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= rewardValues.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>1 &lt;= rewardValues[i] &lt;= 5 * 10<sup>4</sup></code></li> </ul>
Bit Manipulation; Array; Dynamic Programming
Java
import java.math.BigInteger; class Solution { public int maxTotalReward(int[] rewardValues) { int[] nums = Arrays.stream(rewardValues).distinct().sorted().toArray(); BigInteger f = BigInteger.ONE; for (int v : nums) { BigInteger mask = BigInteger.ONE.shiftLeft(v).subtract(BigInteger.ONE); BigInteger shifted = f.and(mask).shiftLeft(v); f = f.or(shifted); } return f.bitLength() - 1; } }
3,181
Maximum Total Reward Using Operations II
Hard
<p>You are given an integer array <code>rewardValues</code> of length <code>n</code>, representing the values of rewards.</p> <p>Initially, your total reward <code>x</code> is 0, and all indices are <strong>unmarked</strong>. You are allowed to perform the following operation <strong>any</strong> number of times:</p> <ul> <li>Choose an <strong>unmarked</strong> index <code>i</code> from the range <code>[0, n - 1]</code>.</li> <li>If <code>rewardValues[i]</code> is <strong>greater</strong> than your current total reward <code>x</code>, then add <code>rewardValues[i]</code> to <code>x</code> (i.e., <code>x = x + rewardValues[i]</code>), and <strong>mark</strong> the index <code>i</code>.</li> </ul> <p>Return an integer denoting the <strong>maximum </strong><em>total reward</em> you can collect by performing the operations optimally.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,1,3,3]</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>During the operations, we can choose to mark the indices 0 and 2 in order, and the total reward will be 4, which is the maximum.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,6,4,3,2]</span></p> <p><strong>Output:</strong> <span class="example-io">11</span></p> <p><strong>Explanation:</strong></p> <p>Mark the indices 0, 2, and 1 in order. The total reward will then be 11, which is the maximum.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= rewardValues.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>1 &lt;= rewardValues[i] &lt;= 5 * 10<sup>4</sup></code></li> </ul>
Bit Manipulation; Array; Dynamic Programming
Python
class Solution: def maxTotalReward(self, rewardValues: List[int]) -> int: nums = sorted(set(rewardValues)) f = 1 for v in nums: f |= (f & ((1 << v) - 1)) << v return f.bit_length() - 1
3,181
Maximum Total Reward Using Operations II
Hard
<p>You are given an integer array <code>rewardValues</code> of length <code>n</code>, representing the values of rewards.</p> <p>Initially, your total reward <code>x</code> is 0, and all indices are <strong>unmarked</strong>. You are allowed to perform the following operation <strong>any</strong> number of times:</p> <ul> <li>Choose an <strong>unmarked</strong> index <code>i</code> from the range <code>[0, n - 1]</code>.</li> <li>If <code>rewardValues[i]</code> is <strong>greater</strong> than your current total reward <code>x</code>, then add <code>rewardValues[i]</code> to <code>x</code> (i.e., <code>x = x + rewardValues[i]</code>), and <strong>mark</strong> the index <code>i</code>.</li> </ul> <p>Return an integer denoting the <strong>maximum </strong><em>total reward</em> you can collect by performing the operations optimally.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,1,3,3]</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>During the operations, we can choose to mark the indices 0 and 2 in order, and the total reward will be 4, which is the maximum.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">rewardValues = [1,6,4,3,2]</span></p> <p><strong>Output:</strong> <span class="example-io">11</span></p> <p><strong>Explanation:</strong></p> <p>Mark the indices 0, 2, and 1 in order. The total reward will then be 11, which is the maximum.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= rewardValues.length &lt;= 5 * 10<sup>4</sup></code></li> <li><code>1 &lt;= rewardValues[i] &lt;= 5 * 10<sup>4</sup></code></li> </ul>
Bit Manipulation; Array; Dynamic Programming
TypeScript
function maxTotalReward(rewardValues: number[]): number { rewardValues.sort((a, b) => a - b); rewardValues = [...new Set(rewardValues)]; let f = 1n; for (const x of rewardValues) { const mask = (1n << BigInt(x)) - 1n; f = f | ((f & mask) << BigInt(x)); } return f.toString(2).length - 1; }
3,182
Find Top Scoring Students
Medium
<p>Table: <code>students</code></p> <pre> +-------------+----------+ | Column Name | Type | +-------------+----------+ | student_id | int | | name | varchar | | major | varchar | +-------------+----------+ student_id is the primary key (combination of columns with unique values) for this table. Each row of this table contains the student ID, student name, and their major. </pre> <p>Table: <code>courses</code></p> <pre> +-------------+----------+ | Column Name | Type | +-------------+----------+ | course_id | int | | name | varchar | | credits | int | | major | varchar | +-------------+----------+ course_id is the primary key (combination of columns with unique values) for this table. Each row of this table contains the course ID, course name, the number of credits for the course, and the major it belongs to. </pre> <p>Table: <code>enrollments</code></p> <pre> +-------------+----------+ | Column Name | Type | +-------------+----------+ | student_id | int | | course_id | int | | semester | varchar | | grade | varchar | +-------------+----------+ (student_id, course_id, semester) is the primary key (combination of columns with unique values) for this table. Each row of this table contains the student ID, course ID, semester, and grade received. </pre> <p>Write a solution to find the students who have <strong>taken</strong> <strong>all courses</strong> offered in their <code>major</code> and have achieved a <strong>grade of A</strong> <strong>in all these courses</strong>.</p> <p>Return <em>the result table ordered by</em> <code>student_id</code> <em>in <strong>ascending</strong> order</em>.</p> <p>The result format is in the following example.</p> <p>&nbsp;</p> <p><strong class="example">Example:</strong></p> <div class="example-block"> <p><strong>Input:</strong></p> <p>students table:</p> <pre class="example-io"> +------------+------------------+------------------+ | student_id | name | major | +------------+------------------+------------------+ | 1 | Alice | Computer Science | | 2 | Bob | Computer Science | | 3 | Charlie | Mathematics | | 4 | David | Mathematics | +------------+------------------+------------------+ </pre> <p>courses table:</p> <pre class="example-io"> +-----------+-----------------+---------+------------------+ | course_id | name | credits | major | +-----------+-----------------+---------+------------------+ | 101 | Algorithms | 3 | Computer Science | | 102 | Data Structures | 3 | Computer Science | | 103 | Calculus | 4 | Mathematics | | 104 | Linear Algebra | 4 | Mathematics | +-----------+-----------------+---------+------------------+ </pre> <p>enrollments table:</p> <pre class="example-io"> +------------+-----------+----------+-------+ | student_id | course_id | semester | grade | +------------+-----------+----------+-------+ | 1 | 101 | Fall 2023| A | | 1 | 102 | Fall 2023| A | | 2 | 101 | Fall 2023| B | | 2 | 102 | Fall 2023| A | | 3 | 103 | Fall 2023| A | | 3 | 104 | Fall 2023| A | | 4 | 103 | Fall 2023| A | | 4 | 104 | Fall 2023| B | +------------+-----------+----------+-------+ </pre> <p><strong>Output:</strong></p> <pre class="example-io"> +------------+ | student_id | +------------+ | 1 | | 3 | +------------+ </pre> <p><strong>Explanation:</strong></p> <ul> <li>Alice (student_id 1) is a Computer Science major and has taken both &quot;Algorithms&quot; and &quot;Data Structures&quot;, receiving an &#39;A&#39; in both.</li> <li>Bob (student_id 2) is a Computer Science major but did not receive an &#39;A&#39; in all required courses.</li> <li>Charlie (student_id 3) is a Mathematics major and has taken both &quot;Calculus&quot; and &quot;Linear Algebra&quot;, receiving an &#39;A&#39; in both.</li> <li>David (student_id 4) is a Mathematics major but did not receive an &#39;A&#39; in all required courses.</li> </ul> <p><b>Note:</b> Output table is ordered by student_id in ascending order.</p> </div>
Database
SQL
# Write your MySQL query statement below SELECT student_id FROM students JOIN courses USING (major) LEFT JOIN enrollments USING (student_id, course_id) GROUP BY 1 HAVING SUM(grade = 'A') = COUNT(major) ORDER BY 1;
3,183
The Number of Ways to Make the Sum
Medium
<p>You have an <strong>infinite</strong> number of coins with values 1, 2, and 6, and <strong>only</strong> 2 coins with value 4.</p> <p>Given an integer <code>n</code>, return the number of ways to make the sum of <code>n</code> with the coins you have.</p> <p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p><strong>Note</strong> that the order of the coins doesn&#39;t matter and <code>[2, 2, 3]</code> is the same as <code>[2, 3, 2]</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>Here are the four combinations: <code>[1, 1, 1, 1]</code>, <code>[1, 1, 2]</code>, <code>[2, 2]</code>, <code>[4]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 12</span></p> <p><strong>Output:</strong> <span class="example-io">22</span></p> <p><strong>Explanation:</strong></p> <p>Note that <code>[4, 4, 4]</code> is <strong>not</strong> a valid combination since we cannot use 4 three times.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>Here are the four combinations: <code>[1, 1, 1, 1, 1]</code>, <code>[1, 1, 1, 2]</code>, <code>[1, 2, 2]</code>, <code>[1, 4]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n &lt;= 10<sup>5</sup></code></li> </ul>
Array; Dynamic Programming
C++
class Solution { public: int numberOfWays(int n) { const int mod = 1e9 + 7; int coins[3] = {1, 2, 6}; int f[n + 1]; memset(f, 0, sizeof(f)); f[0] = 1; for (int x : coins) { for (int j = x; j <= n; ++j) { f[j] = (f[j] + f[j - x]) % mod; } } int ans = f[n]; if (n >= 4) { ans = (ans + f[n - 4]) % mod; } if (n >= 8) { ans = (ans + f[n - 8]) % mod; } return ans; } };
3,183
The Number of Ways to Make the Sum
Medium
<p>You have an <strong>infinite</strong> number of coins with values 1, 2, and 6, and <strong>only</strong> 2 coins with value 4.</p> <p>Given an integer <code>n</code>, return the number of ways to make the sum of <code>n</code> with the coins you have.</p> <p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p><strong>Note</strong> that the order of the coins doesn&#39;t matter and <code>[2, 2, 3]</code> is the same as <code>[2, 3, 2]</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>Here are the four combinations: <code>[1, 1, 1, 1]</code>, <code>[1, 1, 2]</code>, <code>[2, 2]</code>, <code>[4]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 12</span></p> <p><strong>Output:</strong> <span class="example-io">22</span></p> <p><strong>Explanation:</strong></p> <p>Note that <code>[4, 4, 4]</code> is <strong>not</strong> a valid combination since we cannot use 4 three times.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>Here are the four combinations: <code>[1, 1, 1, 1, 1]</code>, <code>[1, 1, 1, 2]</code>, <code>[1, 2, 2]</code>, <code>[1, 4]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n &lt;= 10<sup>5</sup></code></li> </ul>
Array; Dynamic Programming
Go
func numberOfWays(n int) int { const mod int = 1e9 + 7 coins := []int{1, 2, 6} f := make([]int, n+1) f[0] = 1 for _, x := range coins { for j := x; j <= n; j++ { f[j] = (f[j] + f[j-x]) % mod } } ans := f[n] if n >= 4 { ans = (ans + f[n-4]) % mod } if n >= 8 { ans = (ans + f[n-8]) % mod } return ans }
3,183
The Number of Ways to Make the Sum
Medium
<p>You have an <strong>infinite</strong> number of coins with values 1, 2, and 6, and <strong>only</strong> 2 coins with value 4.</p> <p>Given an integer <code>n</code>, return the number of ways to make the sum of <code>n</code> with the coins you have.</p> <p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p><strong>Note</strong> that the order of the coins doesn&#39;t matter and <code>[2, 2, 3]</code> is the same as <code>[2, 3, 2]</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>Here are the four combinations: <code>[1, 1, 1, 1]</code>, <code>[1, 1, 2]</code>, <code>[2, 2]</code>, <code>[4]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 12</span></p> <p><strong>Output:</strong> <span class="example-io">22</span></p> <p><strong>Explanation:</strong></p> <p>Note that <code>[4, 4, 4]</code> is <strong>not</strong> a valid combination since we cannot use 4 three times.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>Here are the four combinations: <code>[1, 1, 1, 1, 1]</code>, <code>[1, 1, 1, 2]</code>, <code>[1, 2, 2]</code>, <code>[1, 4]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n &lt;= 10<sup>5</sup></code></li> </ul>
Array; Dynamic Programming
Java
class Solution { public int numberOfWays(int n) { final int mod = (int) 1e9 + 7; int[] coins = {1, 2, 6}; int[] f = new int[n + 1]; f[0] = 1; for (int x : coins) { for (int j = x; j <= n; ++j) { f[j] = (f[j] + f[j - x]) % mod; } } int ans = f[n]; if (n >= 4) { ans = (ans + f[n - 4]) % mod; } if (n >= 8) { ans = (ans + f[n - 8]) % mod; } return ans; } }
3,183
The Number of Ways to Make the Sum
Medium
<p>You have an <strong>infinite</strong> number of coins with values 1, 2, and 6, and <strong>only</strong> 2 coins with value 4.</p> <p>Given an integer <code>n</code>, return the number of ways to make the sum of <code>n</code> with the coins you have.</p> <p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p><strong>Note</strong> that the order of the coins doesn&#39;t matter and <code>[2, 2, 3]</code> is the same as <code>[2, 3, 2]</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>Here are the four combinations: <code>[1, 1, 1, 1]</code>, <code>[1, 1, 2]</code>, <code>[2, 2]</code>, <code>[4]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 12</span></p> <p><strong>Output:</strong> <span class="example-io">22</span></p> <p><strong>Explanation:</strong></p> <p>Note that <code>[4, 4, 4]</code> is <strong>not</strong> a valid combination since we cannot use 4 three times.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>Here are the four combinations: <code>[1, 1, 1, 1, 1]</code>, <code>[1, 1, 1, 2]</code>, <code>[1, 2, 2]</code>, <code>[1, 4]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n &lt;= 10<sup>5</sup></code></li> </ul>
Array; Dynamic Programming
Python
class Solution: def numberOfWays(self, n: int) -> int: mod = 10**9 + 7 coins = [1, 2, 6] f = [0] * (n + 1) f[0] = 1 for x in coins: for j in range(x, n + 1): f[j] = (f[j] + f[j - x]) % mod ans = f[n] if n >= 4: ans = (ans + f[n - 4]) % mod if n >= 8: ans = (ans + f[n - 8]) % mod return ans
3,183
The Number of Ways to Make the Sum
Medium
<p>You have an <strong>infinite</strong> number of coins with values 1, 2, and 6, and <strong>only</strong> 2 coins with value 4.</p> <p>Given an integer <code>n</code>, return the number of ways to make the sum of <code>n</code> with the coins you have.</p> <p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p> <p><strong>Note</strong> that the order of the coins doesn&#39;t matter and <code>[2, 2, 3]</code> is the same as <code>[2, 3, 2]</code>.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 4</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>Here are the four combinations: <code>[1, 1, 1, 1]</code>, <code>[1, 1, 2]</code>, <code>[2, 2]</code>, <code>[4]</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 12</span></p> <p><strong>Output:</strong> <span class="example-io">22</span></p> <p><strong>Explanation:</strong></p> <p>Note that <code>[4, 4, 4]</code> is <strong>not</strong> a valid combination since we cannot use 4 three times.</p> </div> <p><strong class="example">Example 3:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">n = 5</span></p> <p><strong>Output:</strong> <span class="example-io">4</span></p> <p><strong>Explanation:</strong></p> <p>Here are the four combinations: <code>[1, 1, 1, 1, 1]</code>, <code>[1, 1, 1, 2]</code>, <code>[1, 2, 2]</code>, <code>[1, 4]</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= n &lt;= 10<sup>5</sup></code></li> </ul>
Array; Dynamic Programming
TypeScript
function numberOfWays(n: number): number { const mod = 10 ** 9 + 7; const f: number[] = Array(n + 1).fill(0); f[0] = 1; for (const x of [1, 2, 6]) { for (let j = x; j <= n; ++j) { f[j] = (f[j] + f[j - x]) % mod; } } let ans = f[n]; if (n >= 4) { ans = (ans + f[n - 4]) % mod; } if (n >= 8) { ans = (ans + f[n - 8]) % mod; } return ans; }
3,184
Count Pairs That Form a Complete Day I
Easy
<p>Given an integer array <code>hours</code> representing times in <strong>hours</strong>, return an integer denoting the number of pairs <code>i</code>, <code>j</code> where <code>i &lt; j</code> and <code>hours[i] + hours[j]</code> forms a <strong>complete day</strong>.</p> <p>A <strong>complete day</strong> is defined as a time duration that is an <strong>exact</strong> <strong>multiple</strong> of 24 hours.</p> <p>For example, 1 day is 24 hours, 2 days is 48 hours, 3 days is 72 hours, and so on.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [12,12,30,24,24]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The pairs of indices that form a complete day are <code>(0, 1)</code> and <code>(3, 4)</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [72,48,24,3]</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong></p> <p>The pairs of indices that form a complete day are <code>(0, 1)</code>, <code>(0, 2)</code>, and <code>(1, 2)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= hours.length &lt;= 100</code></li> <li><code>1 &lt;= hours[i] &lt;= 10<sup>9</sup></code></li> </ul>
Array; Hash Table; Counting
C++
class Solution { public: int countCompleteDayPairs(vector<int>& hours) { int cnt[24]{}; int ans = 0; for (int x : hours) { ans += cnt[(24 - x % 24) % 24]; ++cnt[x % 24]; } return ans; } };
3,184
Count Pairs That Form a Complete Day I
Easy
<p>Given an integer array <code>hours</code> representing times in <strong>hours</strong>, return an integer denoting the number of pairs <code>i</code>, <code>j</code> where <code>i &lt; j</code> and <code>hours[i] + hours[j]</code> forms a <strong>complete day</strong>.</p> <p>A <strong>complete day</strong> is defined as a time duration that is an <strong>exact</strong> <strong>multiple</strong> of 24 hours.</p> <p>For example, 1 day is 24 hours, 2 days is 48 hours, 3 days is 72 hours, and so on.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [12,12,30,24,24]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The pairs of indices that form a complete day are <code>(0, 1)</code> and <code>(3, 4)</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [72,48,24,3]</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong></p> <p>The pairs of indices that form a complete day are <code>(0, 1)</code>, <code>(0, 2)</code>, and <code>(1, 2)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= hours.length &lt;= 100</code></li> <li><code>1 &lt;= hours[i] &lt;= 10<sup>9</sup></code></li> </ul>
Array; Hash Table; Counting
Go
func countCompleteDayPairs(hours []int) (ans int) { cnt := [24]int{} for _, x := range hours { ans += cnt[(24-x%24)%24] cnt[x%24]++ } return }
3,184
Count Pairs That Form a Complete Day I
Easy
<p>Given an integer array <code>hours</code> representing times in <strong>hours</strong>, return an integer denoting the number of pairs <code>i</code>, <code>j</code> where <code>i &lt; j</code> and <code>hours[i] + hours[j]</code> forms a <strong>complete day</strong>.</p> <p>A <strong>complete day</strong> is defined as a time duration that is an <strong>exact</strong> <strong>multiple</strong> of 24 hours.</p> <p>For example, 1 day is 24 hours, 2 days is 48 hours, 3 days is 72 hours, and so on.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [12,12,30,24,24]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The pairs of indices that form a complete day are <code>(0, 1)</code> and <code>(3, 4)</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [72,48,24,3]</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong></p> <p>The pairs of indices that form a complete day are <code>(0, 1)</code>, <code>(0, 2)</code>, and <code>(1, 2)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= hours.length &lt;= 100</code></li> <li><code>1 &lt;= hours[i] &lt;= 10<sup>9</sup></code></li> </ul>
Array; Hash Table; Counting
Java
class Solution { public int countCompleteDayPairs(int[] hours) { int[] cnt = new int[24]; int ans = 0; for (int x : hours) { ans += cnt[(24 - x % 24) % 24]; ++cnt[x % 24]; } return ans; } }
3,184
Count Pairs That Form a Complete Day I
Easy
<p>Given an integer array <code>hours</code> representing times in <strong>hours</strong>, return an integer denoting the number of pairs <code>i</code>, <code>j</code> where <code>i &lt; j</code> and <code>hours[i] + hours[j]</code> forms a <strong>complete day</strong>.</p> <p>A <strong>complete day</strong> is defined as a time duration that is an <strong>exact</strong> <strong>multiple</strong> of 24 hours.</p> <p>For example, 1 day is 24 hours, 2 days is 48 hours, 3 days is 72 hours, and so on.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [12,12,30,24,24]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The pairs of indices that form a complete day are <code>(0, 1)</code> and <code>(3, 4)</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [72,48,24,3]</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong></p> <p>The pairs of indices that form a complete day are <code>(0, 1)</code>, <code>(0, 2)</code>, and <code>(1, 2)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= hours.length &lt;= 100</code></li> <li><code>1 &lt;= hours[i] &lt;= 10<sup>9</sup></code></li> </ul>
Array; Hash Table; Counting
Python
class Solution: def countCompleteDayPairs(self, hours: List[int]) -> int: cnt = Counter() ans = 0 for x in hours: ans += cnt[(24 - (x % 24)) % 24] cnt[x % 24] += 1 return ans
3,184
Count Pairs That Form a Complete Day I
Easy
<p>Given an integer array <code>hours</code> representing times in <strong>hours</strong>, return an integer denoting the number of pairs <code>i</code>, <code>j</code> where <code>i &lt; j</code> and <code>hours[i] + hours[j]</code> forms a <strong>complete day</strong>.</p> <p>A <strong>complete day</strong> is defined as a time duration that is an <strong>exact</strong> <strong>multiple</strong> of 24 hours.</p> <p>For example, 1 day is 24 hours, 2 days is 48 hours, 3 days is 72 hours, and so on.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [12,12,30,24,24]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong></p> <p>The pairs of indices that form a complete day are <code>(0, 1)</code> and <code>(3, 4)</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [72,48,24,3]</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong></p> <p>The pairs of indices that form a complete day are <code>(0, 1)</code>, <code>(0, 2)</code>, and <code>(1, 2)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= hours.length &lt;= 100</code></li> <li><code>1 &lt;= hours[i] &lt;= 10<sup>9</sup></code></li> </ul>
Array; Hash Table; Counting
TypeScript
function countCompleteDayPairs(hours: number[]): number { const cnt: number[] = Array(24).fill(0); let ans: number = 0; for (const x of hours) { ans += cnt[(24 - (x % 24)) % 24]; ++cnt[x % 24]; } return ans; }
3,185
Count Pairs That Form a Complete Day II
Medium
<p>Given an integer array <code>hours</code> representing times in <strong>hours</strong>, return an integer denoting the number of pairs <code>i</code>, <code>j</code> where <code>i &lt; j</code> and <code>hours[i] + hours[j]</code> forms a <strong>complete day</strong>.</p> <p>A <strong>complete day</strong> is defined as a time duration that is an <strong>exact</strong> <strong>multiple</strong> of 24 hours.</p> <p>For example, 1 day is 24 hours, 2 days is 48 hours, 3 days is 72 hours, and so on.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [12,12,30,24,24]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong> The pairs of indices that form a complete day are <code>(0, 1)</code> and <code>(3, 4)</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [72,48,24,3]</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong> The pairs of indices that form a complete day are <code>(0, 1)</code>, <code>(0, 2)</code>, and <code>(1, 2)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= hours.length &lt;= 5 * 10<sup>5</sup></code></li> <li><code>1 &lt;= hours[i] &lt;= 10<sup>9</sup></code></li> </ul>
Array; Hash Table; Counting
C++
class Solution { public: long long countCompleteDayPairs(vector<int>& hours) { int cnt[24]{}; long long ans = 0; for (int x : hours) { ans += cnt[(24 - x % 24) % 24]; ++cnt[x % 24]; } return ans; } };
3,185
Count Pairs That Form a Complete Day II
Medium
<p>Given an integer array <code>hours</code> representing times in <strong>hours</strong>, return an integer denoting the number of pairs <code>i</code>, <code>j</code> where <code>i &lt; j</code> and <code>hours[i] + hours[j]</code> forms a <strong>complete day</strong>.</p> <p>A <strong>complete day</strong> is defined as a time duration that is an <strong>exact</strong> <strong>multiple</strong> of 24 hours.</p> <p>For example, 1 day is 24 hours, 2 days is 48 hours, 3 days is 72 hours, and so on.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [12,12,30,24,24]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong> The pairs of indices that form a complete day are <code>(0, 1)</code> and <code>(3, 4)</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [72,48,24,3]</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong> The pairs of indices that form a complete day are <code>(0, 1)</code>, <code>(0, 2)</code>, and <code>(1, 2)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= hours.length &lt;= 5 * 10<sup>5</sup></code></li> <li><code>1 &lt;= hours[i] &lt;= 10<sup>9</sup></code></li> </ul>
Array; Hash Table; Counting
Go
func countCompleteDayPairs(hours []int) (ans int64) { cnt := [24]int{} for _, x := range hours { ans += int64(cnt[(24-x%24)%24]) cnt[x%24]++ } return }
3,185
Count Pairs That Form a Complete Day II
Medium
<p>Given an integer array <code>hours</code> representing times in <strong>hours</strong>, return an integer denoting the number of pairs <code>i</code>, <code>j</code> where <code>i &lt; j</code> and <code>hours[i] + hours[j]</code> forms a <strong>complete day</strong>.</p> <p>A <strong>complete day</strong> is defined as a time duration that is an <strong>exact</strong> <strong>multiple</strong> of 24 hours.</p> <p>For example, 1 day is 24 hours, 2 days is 48 hours, 3 days is 72 hours, and so on.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [12,12,30,24,24]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong> The pairs of indices that form a complete day are <code>(0, 1)</code> and <code>(3, 4)</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [72,48,24,3]</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong> The pairs of indices that form a complete day are <code>(0, 1)</code>, <code>(0, 2)</code>, and <code>(1, 2)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= hours.length &lt;= 5 * 10<sup>5</sup></code></li> <li><code>1 &lt;= hours[i] &lt;= 10<sup>9</sup></code></li> </ul>
Array; Hash Table; Counting
Java
class Solution { public long countCompleteDayPairs(int[] hours) { int[] cnt = new int[24]; long ans = 0; for (int x : hours) { ans += cnt[(24 - x % 24) % 24]; ++cnt[x % 24]; } return ans; } }
3,185
Count Pairs That Form a Complete Day II
Medium
<p>Given an integer array <code>hours</code> representing times in <strong>hours</strong>, return an integer denoting the number of pairs <code>i</code>, <code>j</code> where <code>i &lt; j</code> and <code>hours[i] + hours[j]</code> forms a <strong>complete day</strong>.</p> <p>A <strong>complete day</strong> is defined as a time duration that is an <strong>exact</strong> <strong>multiple</strong> of 24 hours.</p> <p>For example, 1 day is 24 hours, 2 days is 48 hours, 3 days is 72 hours, and so on.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [12,12,30,24,24]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong> The pairs of indices that form a complete day are <code>(0, 1)</code> and <code>(3, 4)</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [72,48,24,3]</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong> The pairs of indices that form a complete day are <code>(0, 1)</code>, <code>(0, 2)</code>, and <code>(1, 2)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= hours.length &lt;= 5 * 10<sup>5</sup></code></li> <li><code>1 &lt;= hours[i] &lt;= 10<sup>9</sup></code></li> </ul>
Array; Hash Table; Counting
Python
class Solution: def countCompleteDayPairs(self, hours: List[int]) -> int: cnt = Counter() ans = 0 for x in hours: ans += cnt[(24 - (x % 24)) % 24] cnt[x % 24] += 1 return ans
3,185
Count Pairs That Form a Complete Day II
Medium
<p>Given an integer array <code>hours</code> representing times in <strong>hours</strong>, return an integer denoting the number of pairs <code>i</code>, <code>j</code> where <code>i &lt; j</code> and <code>hours[i] + hours[j]</code> forms a <strong>complete day</strong>.</p> <p>A <strong>complete day</strong> is defined as a time duration that is an <strong>exact</strong> <strong>multiple</strong> of 24 hours.</p> <p>For example, 1 day is 24 hours, 2 days is 48 hours, 3 days is 72 hours, and so on.</p> <p>&nbsp;</p> <p><strong class="example">Example 1:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [12,12,30,24,24]</span></p> <p><strong>Output:</strong> <span class="example-io">2</span></p> <p><strong>Explanation:</strong> The pairs of indices that form a complete day are <code>(0, 1)</code> and <code>(3, 4)</code>.</p> </div> <p><strong class="example">Example 2:</strong></p> <div class="example-block"> <p><strong>Input:</strong> <span class="example-io">hours = [72,48,24,3]</span></p> <p><strong>Output:</strong> <span class="example-io">3</span></p> <p><strong>Explanation:</strong> The pairs of indices that form a complete day are <code>(0, 1)</code>, <code>(0, 2)</code>, and <code>(1, 2)</code>.</p> </div> <p>&nbsp;</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 &lt;= hours.length &lt;= 5 * 10<sup>5</sup></code></li> <li><code>1 &lt;= hours[i] &lt;= 10<sup>9</sup></code></li> </ul>
Array; Hash Table; Counting
TypeScript
function countCompleteDayPairs(hours: number[]): number { const cnt: number[] = Array(24).fill(0); let ans: number = 0; for (const x of hours) { ans += cnt[(24 - (x % 24)) % 24]; ++cnt[x % 24]; } return ans; }