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https://leetcode.com/problems/car-fleet/discuss/1875553/Python-easy-to-read-and-understand-or-sorting
class Solution: def carFleet(self, target: int, position: List[int], speed: List[int]) -> int: n = len(position) time = [] nums = sorted(zip(position, speed), reverse=True) for x, y in nums: time.append((target-x) / y) ans, prev = 0, 0 for i in range(n): if time[i] > prev: ans += 1 prev = time[i] return ans
car-fleet
Python easy to read and understand | sorting
sanial2001
1
128
car fleet
853
0.501
Medium
13,900
https://leetcode.com/problems/car-fleet/discuss/2778734/Simple-Python3-Implementation
class Solution: def carFleet(self, target: int, position: List[int], speed: List[int]) -> int: values = [[position[i], (target - position[i]) / speed[i]] for i in range(len(position))] stack = [] for car in sorted(values): while len(stack) and stack[-1][1] <= car[1]: stack.pop() stack.append(car) return len(stack)
car-fleet
Simple Python3 Implementation
PartialButton5
0
7
car fleet
853
0.501
Medium
13,901
https://leetcode.com/problems/car-fleet/discuss/2640964/Python-greedy-solution-with-sort
class Solution: def carFleet(self, target: int, position: List[int], speed: List[int]) -> int: position_time = [] for i in range(len(position)): time = (target - position[i]) / speed[i] position_time.append((position[i], time)) position_time.sort(key = lambda x: x[0], reverse = True) print(position_time) res = len(position) prev_time = position_time[0][1] for i in range(1, len(position)): time = position_time[i][1] if time <= prev_time: res -= 1 else: prev_time = time return res
car-fleet
Python greedy solution with sort
michaelniki
0
4
car fleet
853
0.501
Medium
13,902
https://leetcode.com/problems/car-fleet/discuss/2601404/Python-Readable-solution
class Solution: def carFleet(self, target: int, position: List[int], speed: List[int]) -> int: # sort the positions position_speed = sorted(zip(position, speed), reverse=True) # get the arrival time of all cars (distance_to_go / speed) arrivals = [(target - position) * (1/speed) for position, speed in position_speed] # get the maximum amount of fleets we would have if reach target independently fleets = len(position) # iterate over all arrival times and compare to the car further down the road # skip first car in order to be able to compare to something # NOTE: idx is automatically pointing at the car before us, as we start at element 1 for idx, time in enumerate(arrivals[1:]): # we arrive earlier or at the same time as car before us, so we make a fleet # and need to adapt our arrival time if time <= arrivals[idx]: fleets -= 1 arrivals[idx+1] = arrivals[idx] return fleets
car-fleet
[Python] - Readable solution
Lucew
0
63
car fleet
853
0.501
Medium
13,903
https://leetcode.com/problems/car-fleet/discuss/2598994/Python-sorting-stack-Solution
class Solution: def carFleet(self, target: int, position: List[int], speed: List[int]) -> int: # pairs: (pos,speed) stack = [] pairs = sorted([(position[i],speed[i]) for i in range(len(position))]) for i in range(len(pairs) - 1,-1,-1): stack.append((target - pairs[i][0]) / pairs[i][1]) if len(stack) >= 2 and stack[-1] <= stack[-2]: # don't use while here, since a car could only collide with the car right in front of it stack.pop() return len(stack)
car-fleet
Python sorting stack Solution
al5861
0
49
car fleet
853
0.501
Medium
13,904
https://leetcode.com/problems/car-fleet/discuss/1989844/Python-or-O(nlogn)-or-98-faster-or-Commented
class Solution: def carFleet(self, target: int, position: List[int], speed: List[int]) -> int: distSpeed = [] stack = [] # Create an List of tuples which contains (position, speed) values. for i in range(len(position)): distSpeed.append((position[i],speed[i])) # Sort the array as the car which are behind will never be able to overtake the car ahead all they can do is to join the fleet. distSpeed = sorted(distSpeed, reverse=True) # Check if the time taken is more than the car ahead if so than we have a new fleet else if the time taken is less than the # Car ahead it will join the same fleet so the car can basically be ignored. # time taken = distance / speed for dist, speed in distSpeed: distance = target-dist if not stack or (distance/speed)>stack[-1]: stack.append(distance/speed) return len(stack)
car-fleet
Python | O(nlogn) | 98% faster | Commented
CSociety
0
90
car fleet
853
0.501
Medium
13,905
https://leetcode.com/problems/car-fleet/discuss/1973327/Optimal-and-Concise-Solution
class Solution: def carFleet(self, target: int, position: List[int], speed: List[int]) -> int: data = [(target - position[i], speed[i]) for i in range(len(position))] data.sort(key=lambda x:x[0]) stack = [] for distance, speed in data: time = distance / speed if not stack or time > stack[-1]: stack.append(time) return len(stack)
car-fleet
Optimal & Concise Solution
EdwinJagger
0
44
car fleet
853
0.501
Medium
13,906
https://leetcode.com/problems/car-fleet/discuss/477860/python-solution
class Solution: def carFleet(self, target: int, position: List[int], speed: List[int]) -> int: n = len(position) xv = sorted(zip(position,speed)) ans = n for i in range(n-2,-1,-1): if xv[i][1]>xv[i+1][1]: # if the car behind goes faster t_fleet = (xv[i+1][0]-xv[i][0])/(xv[i][1]-xv[i+1][1]) # time when the car behind catches the one in front if xv[i][0]+xv[i][1]*t_fleet<=target: # if the catch-up is before the target position ans -= 1 xv[i] = xv[i+1] # update the state of the car behind by the state of the car in front return ans
car-fleet
python solution
felicia1994
0
96
car fleet
853
0.501
Medium
13,907
https://leetcode.com/problems/car-fleet/discuss/1529278/python3-O(NlogN)
class Solution: # O(NlogN) def carFleet(self, target: int, position: List[int], speed: List[int]) -> int: stack = [] # no. of fleet # pair of distance and speed to sort it pair = [(p,s) for p,s in zip(position,speed) ] # sort the pair based on positions and travesing from reverse order for p,s in sorted(pair)[::-1]: # find the time t = (target - p) /s stack.append(t) if len(stack) >= 2 and stack[-1] <= stack[-2]: # fleet stack.pop() return len(stack) ``` feel free to ask Q... #happytohelpu
car-fleet
python3 - O(NlogN)
Shubham_Muramkar
-1
94
car fleet
853
0.501
Medium
13,908
https://leetcode.com/problems/k-similar-strings/discuss/321201/three-solutions-of-this-problem-good-for-understanding-DFS-DFS-with-memo-and-BFS
class Solution: # DFS def kSimilarity(self, A: str, B: str) -> int: N = len(A) def dfs(A, B, pos): if A == B: return 0 while A[pos] == B[pos]: pos += 1 minCnt = float('inf') for i in range(pos + 1, N): if B[i] == A[pos] and B[i] != A[i]: B[i], B[pos] = B[pos], B[i] tmp = dfs(A, B, pos + 1) + 1 minCnt = min(tmp, minCnt) B[i], B[pos] = B[pos], B[i] return minCnt return dfs(list(A), list(B), 0) # DFS with memorization def kSimilarity1(self, A: str, B: str) -> int: N = len(A) def dfs(A, B, pos): sB = ''.join(B) if sB in map: return map[sB] if A == B: return 0 while A[pos] == B[pos]: pos += 1 minCnt = float('inf') for i in range(pos + 1, N): if B[i] == A[pos] and B[i] != A[i]: B[i], B[pos] = B[pos], B[i] tmp = dfs(A, B, pos + 1) + 1 minCnt = min(tmp, minCnt) B[i], B[pos] = B[pos], B[i] map[sB] = minCnt return minCnt map = collections.defaultdict() return dfs(list(A), list(B), 0) # BFS def kSimilarity2(self, A: str, B: str) -> int: N = len(B) q = collections.deque([B]) visited = set(B) cnt = 0 pos = 0 while q: qSize = len(q) for _ in range(qSize): cur = q.popleft() if cur == A: return cnt pos = 0 while cur[pos] == A[pos]: pos += 1 lCur = list(cur) for i in range(pos + 1, N): if lCur[i] == A[pos] and lCur[i] != A[i]: lCur[i], lCur[pos] = lCur[pos], lCur[i] sCur = ''.join(lCur) if sCur not in visited: q.append(sCur) visited.add(sCur) lCur[i], lCur[pos] = lCur[pos], lCur[i] cnt += 1 return cnt
k-similar-strings
three solutions of this problem, good for understanding DFS, DFS with memo and BFS
shchshhappy
21
2,900
k similar strings
854
0.401
Hard
13,909
https://leetcode.com/problems/k-similar-strings/discuss/2385252/Python-BFS-Solution-(fully-explained-and-commented)
class Solution: def kSimilarity(self, s1: str, s2: str) -> int: #the deque keeps track of the set of strings that we want to perform swaps on #at the start, the deque contains only s1 deque = collections.deque([s1]) #this set wasn't mentioned in the "intuition" part. it helps us avoid doing repeated work by adding the same strings to our deque seen = set() answ=0 #counter for the number of "swaps" done so far while deque: for _ in range(len(deque)): #loops through each string in the deque string = deque.popleft() #gets the first string in the deque if string ==s2: return answ #finds the first non-matching letter in s1 #this satisfies condition 1 of a "useful" swap #ex: this would be s1[3] in the above example i=0 while string[i]==s2[i]: i+=1 #checks all the other letters for potential swaps for j in range(i+1, len(string)): if string[i]==s2[j]!=s1[j]: #checks conditions 2 and 3 of a useful swap #swaps the letters at positions i and j new = string[:i] + string[j] + string[i+1:j] + string[i] + string[j+1:] #adds the "new string" if it was not previously added if new not in seen: seen.add(new) deque.append(new) #record that one more swap was done for each string in the deque answ+=1
k-similar-strings
Python BFS Solution (fully explained & commented)
ahil_io
16
626
k similar strings
854
0.401
Hard
13,910
https://leetcode.com/problems/k-similar-strings/discuss/1521457/Python3-bfs
class Solution: def kSimilarity(self, s1: str, s2: str) -> int: ans = 0 seen = {s1} queue = deque([s1]) while queue: for _ in range(len(queue)): s = queue.popleft() if s == s2: return ans for i in range(len(s)): if s[i] != s2[i]: for j in range(i+1, len(s)): if s[j] != s2[j] and s[j] == s2[i]: ss = s[:i] + s[j] + s[i+1:j] + s[i] + s[j+1:] if ss not in seen: seen.add(ss) queue.append(ss) break ans += 1
k-similar-strings
[Python3] bfs
ye15
3
381
k similar strings
854
0.401
Hard
13,911
https://leetcode.com/problems/k-similar-strings/discuss/2599050/Python-Easy-to-understand-backtracking
class Solution: def kSimilarity(self, s1: str, s2: str) -> int: n = len(s1) arr, s2_arr = list(s1), list(s2) min_steps = float('inf') def helper(steps,i): nonlocal min_steps if steps >= min_steps: return if i == n: min_steps = min(min_steps, steps) return # if character at index i is already correct if arr[i] == s2[i]: helper(steps,i+1) return for j in range(i+1,n): ''' skip if: 1. characters at i and j are the same 2. character at j is not what we need at i 3. character at j is already correctly placed ''' if arr[i] == arr[j] or arr[j] != s2[i] or arr[j] == s2[j]: continue arr[i], arr[j] = arr[j], arr[i] helper(steps+1,i+1) arr[i], arr[j] = arr[j], arr[i] helper(0,0) return min_steps
k-similar-strings
[Python] Easy to understand backtracking
fomiee
0
70
k similar strings
854
0.401
Hard
13,912
https://leetcode.com/problems/k-similar-strings/discuss/1840466/Easy-DP-Solution-using-Cache
class Solution: def kSimilarity(self, s1: str, s2: str) -> int: @cache def dfs(a,b,pos): if a==b : return 0 while a[pos]==b[pos] : pos+=1 a,b=list(a),list(b) ans=10**18 for i in range(pos+1,len(a)): if b[i]==a[pos] and b[i]!=a[i] : b[i],b[pos]=b[pos],b[i] ans=min(ans,dfs(tuple(a),tuple(b),pos+1)+1) b[i],b[pos]=b[pos],b[i] return ans return dfs(tuple(s1),tuple(s2),0)
k-similar-strings
Easy DP Solution using Cache
P3rf3ct0
0
319
k similar strings
854
0.401
Hard
13,913
https://leetcode.com/problems/k-similar-strings/discuss/464826/python-32ms-solution-faster-than-100-with-extremely-small-memory
class Solution: def kSimilarity(self, A: str, B: str) -> int: la = [] lb = [] for a, b in zip(A, B): if a != b: la.append(a) lb.append(b) queue = {''.join(la): 0} while lb: q = {} for pre, swap in queue.items(): if pre[-1] != lb[-1]: eq = [] for i, ch in enumerate(pre[:-1]): if ch == lb[-1] and lb[i] != ch: eq.append(i) if lb[i] == pre[-1]: eq = [i] break for i in eq: tmp = pre[:i] + pre[-1] + pre[i + 1:-1] q[tmp] = min(swap + 1, q.get(tmp, float('inf'))) else: q[pre[:-1]] = min(swap, q.get(pre[:-1], float('inf'))) lb.pop() queue = q return list(queue.values())[0]
k-similar-strings
python 32ms solution faster than 100% with extremely small memory
yutaoli
0
195
k similar strings
854
0.401
Hard
13,914
https://leetcode.com/problems/score-of-parentheses/discuss/2299821/Python-or-faster-than-83-or-easy-understanding-or-explaining-with-comments
class Solution: def scoreOfParentheses(self, s: str) -> int: stk = [0] # temp value to help us for char in s: if char == '(': stk.append(0) # new parent: current sum = 0 else: # An expression will be closed # Find its value: either 1 for empty () or 2 * its sub-expressions # we can calc both with a simple max() value = max(2 * stk.pop(), 1) # Add the expression sum to its parent current sum # Assume we have expression E that is (CHD) # where C, H, D are valid-subexpressions with values 5, 10, 4 # then E is (5+10+4) = (19) = 38 # Every time we finish an expression, we add its value to its parent # get the parent and update its sum with a finished sub-expression stk[-1] += value return stk.pop() ```
score-of-parentheses
Python | faster than 83% | easy-understanding | explaining with comments
Saiko15
3
130
score of parentheses
856
0.65
Medium
13,915
https://leetcode.com/problems/score-of-parentheses/discuss/1080614/Python.-Super-simple-O(1)-space-solution.
class Solution: def scoreOfParentheses(self, S: str) -> int: res, balance = 0, 0 for index, par in enumerate(S): balance += 1 if par == "(" else -1 if index and S[index - 1] + par == "()": res += 2 ** balance return res
score-of-parentheses
Python. Super simple O(1) space solution.
m-d-f
3
443
score of parentheses
856
0.65
Medium
13,916
https://leetcode.com/problems/score-of-parentheses/discuss/939553/Python3-stack-O(N)
class Solution: def scoreOfParentheses(self, S: str) -> int: ans, stack = 0, [] for c in S: if c == "(": stack.append(ans) ans = 0 else: ans = max(1, 2*ans) + stack.pop() return ans
score-of-parentheses
[Python3] stack O(N)
ye15
3
131
score of parentheses
856
0.65
Medium
13,917
https://leetcode.com/problems/score-of-parentheses/discuss/939553/Python3-stack-O(N)
class Solution: def scoreOfParentheses(self, S: str) -> int: ans = k = 0 for i in range(len(S)): k += 1 if S[i] == "(" else -1 if S[i-1:i+1] == "()": ans += 2**k return ans
score-of-parentheses
[Python3] stack O(N)
ye15
3
131
score of parentheses
856
0.65
Medium
13,918
https://leetcode.com/problems/score-of-parentheses/discuss/1080672/Python-or-T-O(n)-S-O(1)-or-Beats-94
class Solution(object): def scoreOfParentheses(self, S): """ :type S: str :rtype: int """ res, balance = 0, 0 for index, ch in enumerate(S): balance = balance+1 if ch == '(' else balance-1 if index and S[index-1] + ch == '()': res += 2 ** balance return res
score-of-parentheses
Python | T-O(n), S-O(1) | Beats 94%
vsahoo
1
101
score of parentheses
856
0.65
Medium
13,919
https://leetcode.com/problems/score-of-parentheses/discuss/2658545/Python-Stack-Implementation-O(N)-time-complexity
class Solution: def scoreOfParentheses(self, s: str) -> int: stack=[] for i in s: if i=="(": stack.append("(") else: if stack[-1]=="(": stack.pop() stack.append(1) else: sum1=0 while stack[-1]!="(": a=stack.pop() sum1+=a stack.pop() stack.append(2*sum1) return sum(stack)
score-of-parentheses
Python - Stack Implementation O(N) time complexity
utsa_gupta
0
5
score of parentheses
856
0.65
Medium
13,920
https://leetcode.com/problems/score-of-parentheses/discuss/2656497/Score-of-Parentheses-oror-Python3-oror-Stack
class Solution: def scoreOfParentheses(self, s: str) -> int: stack=[] for i in range(len(s)): if s[i]=='(': stack.append(-1) else: if stack[-1]==-1: stack.pop() stack.append(1) else: t=0 while stack[-1]!=-1: t+=stack.pop() stack.pop() stack.append(2*t) return sum(stack)
score-of-parentheses
Score of Parentheses || Python3 || Stack
shagun_pandey
0
5
score of parentheses
856
0.65
Medium
13,921
https://leetcode.com/problems/score-of-parentheses/discuss/2656405/easy-python-solution-using-stack
class Solution: def scoreOfParentheses(self, s: str) -> int: s1=[] for i in s: if i=="(": s1.append(i) else: if s1[-1]=="(": s1.pop() s1.append(1) else: sumi=0 while s1[-1]!="(": sumi+=s1.pop() s1.pop() s1.append(2*sumi) return sum(s1)
score-of-parentheses
easy python solution using stack
insane_me12
0
5
score of parentheses
856
0.65
Medium
13,922
https://leetcode.com/problems/score-of-parentheses/discuss/2656182/python-easy-solution-in-0(n)-and-space-in0(1)-with-explaination
class Solution: def scoreOfParentheses(self, s: str) -> int: cur=0 stack=[] #making stack for i in s: if i=='(': stack.append(cur) # if found '(' then push cur i.e 0 in stack cur=0 # make cur as 0 again else: cur=stack.pop()+max(cur*2,1) #if not found open "(" then pop cur from stack and add with the maximum of cur and 1 return cur
score-of-parentheses
python easy solution in 0(n) and space in0(1) with explaination
tush18
0
9
score of parentheses
856
0.65
Medium
13,923
https://leetcode.com/problems/score-of-parentheses/discuss/2183901/Best-Recursive-Solution-oror-No-Stack-Used-oror-Easy-Approach
class Solution: def __init__(self): self.i = 0 def scoreOfParentheses(self, s: str) -> int: score = 0 length = len(s) while self.i < length: bracket = s[self.i] self.i += 1 if bracket == "(": if s[self.i] == ")": score += 1 self.i += 1 else: score += 2*self.scoreOfParentheses(s) else: return score return score
score-of-parentheses
Best Recursive Solution || No Stack Used || Easy Approach
Vaibhav7860
0
45
score of parentheses
856
0.65
Medium
13,924
https://leetcode.com/problems/score-of-parentheses/discuss/1858473/Terrible-but-Solution-that-doesn't-really-use-any-algorithm-or-database-concepts
class Solution: def scoreOfParentheses(self, s: str) -> int: arr = [""]*len(s) i = len(s)-1 openings = 0 while i >= 0: if s[i] == ")": if s[i-1] == "(": arr[i-1] = "+1" else: arr[i] = ")" j = i closings = 1 while closings > 0: j-=1 if s[j] == ")": closings += 1 elif s[j] == "(": closings -= 1 arr[j] = "2*(" i-=1 equation = "".join(arr)
score-of-parentheses
Terrible but Solution that doesn't really use any algorithm or database concepts
bomb483
0
12
score of parentheses
856
0.65
Medium
13,925
https://leetcode.com/problems/score-of-parentheses/discuss/1858065/Readable-Python-solution-with-explanation-faster-than-99.91
class Solution: def scoreOfParentheses(self, s: str) -> int: # 1st part # Let's create a_plus_b list. # s == "(())(()()(()))()" # a_plus_b == ['(())', '(()()(()))', '()'] a_plus_b = [] count = 0 start = 0 for i in range(len(s)): if s[i] == "(": count += 1 elif s[i] == ")": count -= 1 if count == 0: a_plus_b.append(s[start:i + 1]) start = i + 1 # 2nd part # We have to iterate over each sub_string in a_plus_b list. solution = 0 for sub_string in a_plus_b: sub_solution = 0 # We have to iterate over each parenthesis (p) in sub_string. # We simply count p, count = 0 # count += 1 if p == "(" # count -= 1 if p == ")" # also if p == ")" we have to add 2**count to sub_solution # but only if previous parnethesis was "(", that's what check_point is used for # "( ( ) ( ) ( ( ) ) )" p # 1 2 1 2 1 2 3 2 1 0 count # + + + x x + valid as previous parenthesis is "(" # x invalid as previous parentehsis is ")" # if valid (+): # sub_solution += 2**count count = 0 check_point = 1 for p in sub_string: if p == "(": count += 1 if check_point == 0: check_point = 1 elif p == ")": count -= 1 if check_point == 1: solution += 2 ** count check_point = 0 solution += sub_solution sub_solution = 0 return solution
score-of-parentheses
Readable Python solution with explanation [faster than 99.91%]
zebra-f
0
23
score of parentheses
856
0.65
Medium
13,926
https://leetcode.com/problems/score-of-parentheses/discuss/1857979/Runtime%3A-28-ms-faster-than-94.45-of-Python3.-O(1)-extra-memory-usage
class Solution: def scoreOfParentheses(self, s: str) -> int: multiplier = 1 score = 0 closing = False for elem in s: if elem == "(": multiplier <<= 1 closing = False else: multiplier >>= 1 score += multiplier * (not closing) closing = True return score
score-of-parentheses
Runtime: 28 ms, faster than 94.45% of Python3. O(1) extra memory usage
mg1999
0
24
score of parentheses
856
0.65
Medium
13,927
https://leetcode.com/problems/score-of-parentheses/discuss/1857206/Python3-Solution-with-using-stack
class Solution: def scoreOfParentheses(self, s: str) -> int: stack = [0] for c in s: if c == '(': stack.append(0) else: elem = stack.pop() stack[-1] += max(2 * elem, 1) return stack[-1]
score-of-parentheses
[Python3] Solution with using stack
maosipov11
0
8
score of parentheses
856
0.65
Medium
13,928
https://leetcode.com/problems/score-of-parentheses/discuss/1856884/Python-or-TC-O(N)SC-O(N)-or-faster-than-98.6-or-Easy-to-understand-2-diff-approaches
class Solution(object): def scoreOfParentheses(self, s): """ :type s: str :rtype: int """ stack = [] score = 0 for par in s: if par == "(": stack.append(score) score = 0 else: score += stack.pop()+ max(score,1) return score
score-of-parentheses
Python | TC-O(N)/SC-O(N) | faster than 98.6% | Easy to understand 2 diff approaches
Patil_Pratik
0
26
score of parentheses
856
0.65
Medium
13,929
https://leetcode.com/problems/score-of-parentheses/discuss/1856884/Python-or-TC-O(N)SC-O(N)-or-faster-than-98.6-or-Easy-to-understand-2-diff-approaches
class Solution(object): def scoreOfParentheses(self, s): """ :type s: str :rtype: int """ stack = [] score = 0 for par in s: val = 0 if par == "(": stack.append(0) else: while stack[-1] != 0: val += stack.pop() val = max(2*val, 1) stack.pop() stack.append(val) while stack: score += stack.pop() return score
score-of-parentheses
Python | TC-O(N)/SC-O(N) | faster than 98.6% | Easy to understand 2 diff approaches
Patil_Pratik
0
26
score of parentheses
856
0.65
Medium
13,930
https://leetcode.com/problems/score-of-parentheses/discuss/1856659/Python-Simple-Python-Solution-Using-Stack-and-Iterative-Approach
class Solution: def scoreOfParentheses(self, s: str) -> int: score = 0 stack = [] for i in s: if i == '(': stack.append(i) else: top = stack.pop() if top == '(' and i == ')': stack.append(1) else: score = 0 while top != '(': score = score + top top = stack.pop() stack.append(2*score) return sum(stack)
score-of-parentheses
[ Python ] ✔✔ Simple Python Solution Using Stack and Iterative Approach 🔥✌
ASHOK_KUMAR_MEGHVANSHI
0
40
score of parentheses
856
0.65
Medium
13,931
https://leetcode.com/problems/score-of-parentheses/discuss/1856566/Python3-96.62-or-Recurssion-and-Stack-or-Well-explained-and-Easy-Implementation
class Solution: def scoreOfParentheses(self, s: str) -> int: if not s: return 0 # use to stack to cancel the left most parentheses st = [] for i, c in enumerate(s): # add any left if c == '(': st.append(1) else: # pop right st.pop() # if stack is empty, then we find where is the right part for the left most parentheses if not st: # if there is nothing in between, and 1 as base case if i == 1: return 1 + self.scoreOfParentheses(s[2:]) # otherwise, recursive to solve the subproblem return 2 * self.scoreOfParentheses(s[1:i]) + self.scoreOfParentheses(s[i+1:])
score-of-parentheses
Python3 96.62% | Recurssion & Stack | Well explained & Easy Implementation
doneowth
0
18
score of parentheses
856
0.65
Medium
13,932
https://leetcode.com/problems/score-of-parentheses/discuss/1677933/No-Stack-Very-Easy-to-Understand-O(n)-and-O(1)
class Solution(object): def scoreOfParentheses(self, S): depth = -1 total = 0 for index, element in enumerate(S): if element == '(': depth += 1 elif element == ')' and S[index - 1] == '(': total += 2 ** depth depth -= 1 else: depth -= 1 return total
score-of-parentheses
No Stack - Very Easy to Understand - O(n) & O(1)
leeik
0
47
score of parentheses
856
0.65
Medium
13,933
https://leetcode.com/problems/score-of-parentheses/discuss/1677933/No-Stack-Very-Easy-to-Understand-O(n)-and-O(1)
class Solution: def scoreOfParentheses(self, s: str) -> int: total_sum = 0 multiplier = 1 for index, value in enumerate(s): if value == '(': if s[index + 1] == ')': total_sum += multiplier * 1 else: multiplier *= 2 else: if s[index - 1] == ')': multiplier //= 2 return total_sum
score-of-parentheses
No Stack - Very Easy to Understand - O(n) & O(1)
leeik
0
47
score of parentheses
856
0.65
Medium
13,934
https://leetcode.com/problems/score-of-parentheses/discuss/1621479/Python-Easy-Solution-or-Faster-than-99
class Solution: def scoreOfParentheses(self, s: str) -> int: # Approach 1: stck = [0] for brac in s: if brac == "(": stck.append(0) else: fir = stck.pop() sec = stck.pop() stck.append(sec+max(2*fir, 1)) return stck.pop() # Approach 2: stck = [0] scre = 0 for brac in s: if brac == "(": stck.append(0) else: fir = stck.pop() stck[-1] += max(2*fir, 1) return stck.pop()
score-of-parentheses
Python Easy Solution | Faster than 99% ✔
leet_satyam
0
105
score of parentheses
856
0.65
Medium
13,935
https://leetcode.com/problems/score-of-parentheses/discuss/1191550/Python3-simple-solution-using-stack
class Solution: def scoreOfParentheses(self, S: str) -> int: z = [0] for i in S: if i == '(': z.append(0) else: x = z.pop() z[-1] += max(2*x,1) return z[0]
score-of-parentheses
Python3 simple solution using stack
EklavyaJoshi
0
82
score of parentheses
856
0.65
Medium
13,936
https://leetcode.com/problems/score-of-parentheses/discuss/1081769/Python3-easy-to-understand
class Solution: def scoreOfParentheses(self, S: str) -> int: if not S: return 0 n = len(S) power = deque() val = {} # {index:val} res = 0 for i in range(n): if S[i] == "(": power.append(i) else: x = power.pop() if x+1 == i: val[i-1] = 1 else: for k,v in val.items(): if x < k: val[k] *= 2 return sum(val.values())
score-of-parentheses
Python3 easy to understand
2017JAMESFU
0
57
score of parentheses
856
0.65
Medium
13,937
https://leetcode.com/problems/score-of-parentheses/discuss/843810/Intuitive-approach-by-accumulating-number-of-left-parenthesis-and-flag-to-calculate-score-or-not
class Solution: def scoreOfParentheses(self, S: str) -> int: left_parenthesis_count = 0 score = 0 score_flag = False for c in S: if c == '(': left_parenthesis_count += 1 score_flag = True else: left_parenthesis_count -= 1 if score_flag: score += pow(2, left_parenthesis_count) score_flag = False return score
score-of-parentheses
Intuitive approach by accumulating number of left parenthesis and flag to calculate score or not
puremonkey2001
0
50
score of parentheses
856
0.65
Medium
13,938
https://leetcode.com/problems/minimum-cost-to-hire-k-workers/discuss/1265778/Python3-greedy-(priority-queue)
class Solution: def mincostToHireWorkers(self, quality: List[int], wage: List[int], k: int) -> float: ans, rsm = inf, 0 pq = [] # max-heap for q, w in sorted(zip(quality, wage), key=lambda x: x[1]/x[0]): rsm += q heappush(pq, -q) if len(pq) > k: rsm += heappop(pq) if len(pq) == k: ans = min(ans, rsm * w/q) return ans
minimum-cost-to-hire-k-workers
[Python3] greedy (priority queue)
ye15
1
83
minimum cost to hire k workers
857
0.521
Hard
13,939
https://leetcode.com/problems/minimum-cost-to-hire-k-workers/discuss/2637950/Python3-or-Priority-Queue
class Solution: def mincostToHireWorkers(self, quality: List[int], wage: List[int], k: int) -> float: n=len(wage) arr=[[wage[i]/quality[i],quality[i]] for i in range(n)] arr.sort(key=lambda x:x[0]) kSmallest=0 pq=[] for i in range(k): heapq.heappush(pq,-arr[i][1]) kSmallest+=arr[i][1] minCost=arr[k-1][0]*kSmallest for c in range(k,n): if pq and abs(pq[0])>arr[c][1]: qRem=-heappop(pq) kSmallest-=qRem kSmallest+=arr[c][1] heappush(pq,-arr[c][1]) minCost=min(minCost,arr[c][0]*kSmallest) return minCost
minimum-cost-to-hire-k-workers
[Python3] | Priority Queue
swapnilsingh421
0
6
minimum cost to hire k workers
857
0.521
Hard
13,940
https://leetcode.com/problems/minimum-cost-to-hire-k-workers/discuss/2609100/Python3-Solution-or-O(nlogn)-or-Heap
class Solution: def mincostToHireWorkers(self, Q, W, K): ans, csum, H = float('inf'), 0, [] for q, w in sorted(zip(Q, W), key = lambda x: x[1] / x[0]): csum += q heapq.heappush(H, -q) if len(H) > K: csum += heapq.heappop(H) if len(H) == K: ans = min(ans, csum * w / q) return ans
minimum-cost-to-hire-k-workers
✔ Python3 Solution | O(nlogn) | Heap
satyam2001
0
14
minimum cost to hire k workers
857
0.521
Hard
13,941
https://leetcode.com/problems/minimum-cost-to-hire-k-workers/discuss/1258759/Python-Solution-using-heap
class Solution: def mincostToHireWorkers(self, quality: List[int], wage: List[int], K: int) -> float: workers=[] for w,q in zip(wage, quality): workers.append([float(w) / q, q] ) workers.sort() print(workers) res = float('inf') qsum = 0 heap = [] for r, q in workers: heapq.heappush(heap, -q) #print(heap) qsum += q if len(heap) > K: qsum += heapq.heappop(heap) if len(heap) == K: res = min(res, qsum * r) print(heap) return res
minimum-cost-to-hire-k-workers
Python Solution using heap
jaipoo
0
130
minimum cost to hire k workers
857
0.521
Hard
13,942
https://leetcode.com/problems/mirror-reflection/discuss/2376355/Python3-oror-4-lines-geometry-w-explanation-oror-TM%3A-9281
class Solution: def mirrorReflection(self, p: int, q: int) -> int: L = lcm(p,q) if (L//q)%2 == 0: return 2 return (L//p)%2
mirror-reflection
Python3 || 4 lines, geometry, w/ explanation || T/M: 92%/81%
warrenruud
73
3,400
mirror reflection
858
0.633
Medium
13,943
https://leetcode.com/problems/mirror-reflection/discuss/2376355/Python3-oror-4-lines-geometry-w-explanation-oror-TM%3A-9281
class Solution: def mirrorReflection(self, p: int, q: int) -> int: # L*G = p*q <=> L/q = p/G <=> L/p = q/G G = gcd(p,q) p//= G q//= G if p%2 == 0: return 2 return q%2
mirror-reflection
Python3 || 4 lines, geometry, w/ explanation || T/M: 92%/81%
warrenruud
73
3,400
mirror reflection
858
0.633
Medium
13,944
https://leetcode.com/problems/mirror-reflection/discuss/939784/Beautiful-easy-solution(with-explanation)
class Solution: def mirrorReflection(self, p: int, q: int) -> int: def step(right, up, distance): if distance == p: return 1 if (up and right) else 2 if up else 0 elif distance > p: return step(not right, not up, distance % p) else: return step(not right, up, distance+q) return step(True, True, q)
mirror-reflection
Beautiful easy solution(with explanation)
code_much_more
6
354
mirror reflection
858
0.633
Medium
13,945
https://leetcode.com/problems/mirror-reflection/discuss/2377770/Faster-than-100-python-users-oror-Easy-Python-Solution-oror-GCD-LCM-Solution
class Solution(object): def gcd(self,a,b): if a == 0: return b return self.gcd(b % a, a) def lcm(self,a,b): return (a / self.gcd(a,b))* b def mirrorReflection(self, p,q): lcm=self.lcm(p,q) m=lcm//p n=lcm//q if n%2==0: return 2 if m%2==0: return 0 return 1 # basically you can just ignore the north wall and imagine the mirrors # as two parallel mirrors with just extending east and west walls and the end points of east walls are made of 0 reflector then 1 reflector the oth the 1th and so onn.... # eventually we gotta find the point where m*p=n*q # and we can find m and n by lcm of p and q # now the consept is simple ..... # if number of extensions of q(ie n) is even that means the end reflection must have happened on west wall ie. reflector 2 else # else there are two possibility reflector 1 or 0 which depends on the value of m(ie. the full fledged square extentions) if its even or odd
mirror-reflection
Faster than 100%😍🎆 python users || Easy Python Solution🤑 || GCD ,LCM Solution😎
ChinnaTheProgrammer
3
92
mirror reflection
858
0.633
Medium
13,946
https://leetcode.com/problems/mirror-reflection/discuss/2377324/Python-or-Java-or-Easy-Solution-using-simple-geometric-observation-or-Commented-code
class Solution: def mirrorReflection(self, p: int, q: int) -> int: ''' Using simple geometry and just by observing we can decide where will the ray hit. for example: p = 2, q = 1; the ray first meets 2nd receptor after it gets reflected for 1 time p = 3, q = 1; the ray first meets 1st receptor after it gets reflected for 2 times. From the given examples one can easly observe that 1:if p is even and q is odd, it'll surely hit 2nd receptor for the first time 2:if both p and q is odd, it'll surely hit 1st receptor for the first time ''' # base case if both p and q are equal, it will always hit receptor 1, # irrespective of their nature if p == q: return 1 while p % 2 == 0 and q % 2 == 0: p //= 2 q //= 2 if p % 2 == 1 and q % 2 == 0: return 0 elif p % 2 == 1 and q % 2 == 1: return 1 elif p % 2 == 0 and q % 2 == 1: return 2
mirror-reflection
Python | Java | Easy Solution using simple geometric observation | Commented code
__Asrar
2
39
mirror reflection
858
0.633
Medium
13,947
https://leetcode.com/problems/mirror-reflection/discuss/2376238/Python-solution-using-directions
class Solution: def mirrorReflection(self, p: int, q: int) -> int: if p == q: return 1 height = q right, up = False, True while 1: if height + q == p: if right and up: return 1 elif not right and up: return 2 else: return 0 elif height + q < p: height += q right = not right else: height += q height %= p right = not right up = not up
mirror-reflection
Python solution using directions
ToORu124124
2
205
mirror reflection
858
0.633
Medium
13,948
https://leetcode.com/problems/mirror-reflection/discuss/2376193/Python-Simple-and-Easy-Solution
class Solution: def mirrorReflection(self, p: int, q: int) -> int: while p%2 == 0 and q%2 == 0: p = p/2 q = q/2 if p%2 == 0 and q%2 != 0: return 2 elif p%2 != 0 and q%2 != 0: return 1 return 0
mirror-reflection
Python - Simple and Easy Solution
dayaniravi123
1
117
mirror reflection
858
0.633
Medium
13,949
https://leetcode.com/problems/mirror-reflection/discuss/2383445/Python-Solution-with-using-math
class Solution: def mirrorReflection(self, p: int, q: int) -> int: m, n = 1, 1 while p * m != q * n: n += 1 m = n * q // p """ n - odd = > number of reflection - even = > right side (0 or 1) """ if m % 2 == 0 and n % 2 != 0: return 0 if m % 2 != 0 and n % 2 != 0: return 1 if m % 2 != 0 and n % 2 == 0: return 2 return -1
mirror-reflection
[Python] Solution with using math
maosipov11
0
8
mirror reflection
858
0.633
Medium
13,950
https://leetcode.com/problems/mirror-reflection/discuss/2380266/Fast-1-Line-Solution-(And-more-understandable-expanded-solution)
class Solution: def mirrorReflection(self, length: int, dist: int) -> int: return (lcm(length, dist) // length % 2) * ((lcm(length, dist) // dist - 1) % 2 + 1)
mirror-reflection
Fast 1 Line Solution (And more understandable expanded solution)
RobbyRivenbark
0
38
mirror reflection
858
0.633
Medium
13,951
https://leetcode.com/problems/mirror-reflection/discuss/2380266/Fast-1-Line-Solution-(And-more-understandable-expanded-solution)
class Solution: def mirrorReflection(self, length: int, dist: int) -> int: common = 0 bounces = -1 while common < length or common % length != 0 : common += dist bounces += 1 cycles = common // length if cycles % 2 == 0 : return 0 return bounces % 2 + 1
mirror-reflection
Fast 1 Line Solution (And more understandable expanded solution)
RobbyRivenbark
0
38
mirror reflection
858
0.633
Medium
13,952
https://leetcode.com/problems/mirror-reflection/discuss/2380144/Easy-python-solution-or-Mirror-Reflection
class Solution: def mirrorReflection(self, p: int, q: int) -> int: if p % 2 == 0 and q % 2 != 0: return 2 elif p % 2 != 0 and q % 2 == 0: return 0 elif p % 2 != 0 and q % 2 != 0: return 1 else: if p == q: return 1 else: return self.mirrorReflection(p/2,q/2)
mirror-reflection
Easy python solution | Mirror Reflection
nishanrahman1994
0
15
mirror reflection
858
0.633
Medium
13,953
https://leetcode.com/problems/mirror-reflection/discuss/2378735/Python-3-Clear-solution
class Solution: def mirrorReflection(self, p: int, q: int) -> int: # x, y - first integer coordinates of ray gcd = self._gcd(p, q) x = p // gcd y = q // gcd up_flip = (y % 2 == 0) right_flip = (x % 2 == 0) if up_flip and right_flip: raise RuntimeError('ray returned to the starting point') if up_flip: return 0 if right_flip: return 2 return 1 def _gcd(self, a, b): if a > b: a, b = b, a while b % a != 0: tmp = a a = b % a b = tmp return a
mirror-reflection
[Python 3] Clear solution
Deimvis
0
38
mirror reflection
858
0.633
Medium
13,954
https://leetcode.com/problems/mirror-reflection/discuss/2377728/GolangPython-Solution
class Solution: def mirrorReflection(self, p: int, q: int) -> int: corners = {(0,1):0, (p,1):1, (p,0):2} i = 0 j = 0 while True: i+=q j+=1 i = i % (2*p) j = j % 2 if (i,j) in corners: return corners[(i,j)]
mirror-reflection
Golang/Python Solution
vtalantsev
0
23
mirror reflection
858
0.633
Medium
13,955
https://leetcode.com/problems/mirror-reflection/discuss/2377728/GolangPython-Solution
class Solution: def mirrorReflection(self, p: int, q: int) -> int: corners = {(0,1):0, (p,1):1, (0,0):2, (p,0):2} lcm = (p * q) // math.gcd(p , q) # Least common multiple j = (lcm // q) % 2 i = lcm % (2*p) return corners[(i,j)]
mirror-reflection
Golang/Python Solution
vtalantsev
0
23
mirror reflection
858
0.633
Medium
13,956
https://leetcode.com/problems/mirror-reflection/discuss/2377397/Python-Intuitive-Solution
class Solution: def mirrorReflection(self, p: int, q: int) -> int: l = lcm(p,q) if l//p % 2 == 0: return 0 else: return 2 if l//q %2 == 0 else 1
mirror-reflection
Python Intuitive Solution
harsh30199
0
4
mirror reflection
858
0.633
Medium
13,957
https://leetcode.com/problems/mirror-reflection/discuss/2377224/Python-Fast-solution-(with-explanations)
class Solution: def mirrorReflection(self, p: int, q: int) -> int: reducedP, reducedQ = p, q while True: reducedPMod2, reducedQMod2 = reducedP % 2, reducedQ % 2 if reducedPMod2 == 0: if reducedQMod2 == 0: reducedP >>= 1 reducedQ >>= 1 else: return 2 elif reducedQMod2 == 0: return 0 else: return 1
mirror-reflection
[Python] Fast solution (with explanations)
RegInt
0
24
mirror reflection
858
0.633
Medium
13,958
https://leetcode.com/problems/mirror-reflection/discuss/2376890/%22python%22-simple-solution-for-you-%3A)
class Solution: def mirrorReflection(self, p: int, q: int) -> int: ext = q reflection = p while ext % 2 == 0 and reflection % 2 == 0: ext /= 2 reflection /= 2 if ext % 2 == 0 and reflection % 2 != 0: return 0 if ext % 2 == 1 and reflection % 2 == 0: return 2 if ext % 2 == 1 and reflection % 2 != 0: return 1 return -1
mirror-reflection
"python" simple solution for you :)
anandchauhan8791
0
23
mirror reflection
858
0.633
Medium
13,959
https://leetcode.com/problems/mirror-reflection/discuss/940454/Python3-Math-log(MN)
class Solution: def mirrorReflection(self, p: int, q: int) -> int: if q == 0: return 0 # edge case g = gcd(p, q) p, q = p//g, q//g if p&amp;1 and q&amp;1: return 1 elif p&amp;1 and not q&amp;1: return 0 elif not p&amp;1 and q&amp;1: return 2
mirror-reflection
[Python3] Math log(MN)
ye15
0
67
mirror reflection
858
0.633
Medium
13,960
https://leetcode.com/problems/mirror-reflection/discuss/940454/Python3-Math-log(MN)
class Solution: def mirrorReflection(self, p: int, q: int) -> int: eps = 1e-5 x = y = 0 dx, dy = p, q while True: if abs(x-p) + abs(y-0) < eps: return 0 if abs(x-p) + abs(y-p) < eps: return 1 if abs(x-0) + abs(y-p) < eps: return 2 xx = x + dx yy = y + dy if not 0 <= xx <= p: xx = max(0, min(p, xx)) yy = y + dy/dx*(xx - x) if not 0 <= yy <= p: yy = max(0, min(p, yy)) xx = x + dx/dy*(yy - y) x, y = xx, yy if xx in (0, p): dx *= -1 if yy in (0, p): dy *= -1
mirror-reflection
[Python3] Math log(MN)
ye15
0
67
mirror reflection
858
0.633
Medium
13,961
https://leetcode.com/problems/mirror-reflection/discuss/939149/Mirror-Reflection-or-Python3-One-liner
class Solution: def mirrorReflection(self, p: int, q: int) -> int: return abs(~(not((mul * p // q) % 2))) if (mul := q // math.gcd(p, q)) % 2 else 0
mirror-reflection
Mirror Reflection | Python3 One-liner
hangyu1130
0
62
mirror reflection
858
0.633
Medium
13,962
https://leetcode.com/problems/mirror-reflection/discuss/388427/Solution-in-Python-3-(two-lines)
class Solution: def mirrorReflection(self, p: int, q: int) -> int: g = math.gcd(p,q) return 2 if not p//g % 2 else q//g % 2 - Junaid Mansuri (LeetCode ID)@hotmail.com
mirror-reflection
Solution in Python 3 (two lines)
junaidmansuri
0
316
mirror reflection
858
0.633
Medium
13,963
https://leetcode.com/problems/buddy-strings/discuss/2790774/Python-oror-Beginner-Friendly-oror-98-faster-oror-O(n)
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: freq1=[0]*26 freq2=[0]*26 diff =0 if(len(s)!=len(goal)): return False for i in range(len(s)): if(s[i]!=goal[i]): diff+=1 freq1[ord(s[i])-ord('a')]+=1 freq2[ord(goal[i])-ord('a')]+=1 unique= True for idx in range(len(freq1)): if(freq1[idx]!=freq2[idx]): return False if(freq1[idx]>1): unique = False if(diff==2 or (unique==False and diff==0)): return True
buddy-strings
Python || Beginner Friendly || 98% faster || O(n)
hasan2599
1
176
buddy strings
859
0.291
Easy
13,964
https://leetcode.com/problems/buddy-strings/discuss/2186221/Python3-O(n)-oror-O(26)-Runtime%3A-40ms-78.04-memory%3A-14.2mb-60.39
class Solution: # O(n) || O(26) # Runtime: 40ms 78.04% memory: 14.2mb 60.39% def buddyStrings(self, string: str, goal: str) -> bool: left, right = 0, len(string) - 1 if len(string) != len(goal): return False if string == goal and len(set(string)) < len(string): return True difference = [] for i in range(len(string)): if string[i] != goal[i]: difference.append((string[i], goal[i])) if len(difference) == 2 and difference[0] == difference[-1][::-1]: return True return False
buddy-strings
Python3 O(n) || O(26) # Runtime: 40ms 78.04% memory: 14.2mb 60.39%
arshergon
1
148
buddy strings
859
0.291
Easy
13,965
https://leetcode.com/problems/buddy-strings/discuss/2123105/Easy-to-understand
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: if len(s) != len(goal): return False if s == goal and len(set(s)) < len(goal): return True diff = [(a, b) for a, b in zip(s, goal) if a != b] return len(diff) == 2 and diff[0] == diff[1][::-1]
buddy-strings
Easy to understand
writemeom
1
168
buddy strings
859
0.291
Easy
13,966
https://leetcode.com/problems/buddy-strings/discuss/1777302/Python-Solution-or-O-(n)
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: index =[] if len(s)==1: return False if s==goal and len(set(s))<len(s): return True; for i in range(len(s)): if s[i]!=goal[i]: index.append(i) if(len(index)!=2): return False; new_s = list(s) swap1 = new_s[index[0]] swap2 = new_s[index[1]] new_s[index[0]] = swap2 new_s[index[1]] = swap1 new_s = ''.join(new_s) if new_s==goal: return True else: return False
buddy-strings
Python Solution | O (n)
pkprasad1996
1
175
buddy strings
859
0.291
Easy
13,967
https://leetcode.com/problems/buddy-strings/discuss/1501870/Easy-well-commented-Python-solution
class Solution: def buddyStrings(self, A: str, B: str) -> bool: if len(A)!=len(B) or set(A)!=set(B): return False if A==B: #must have atleast 1 rep char return len(A)!=len(set(A)) #A and B now same length, lets swap firstMissMatch=0 flagOK=0 for a,b in zip(A,B): if a==b: continue #if letters are qual just continue if not firstMissMatch: #if this is the firstMistMatch, flip firstMissMatch flap to 1 and store the chars swapA,swapB=a,b firstMissMatch=1 elif flagOK==0: #i.e: this is the 2nd mismatch, need to check if the chars to be swapped are equal to the previous mismatch flagOK=1 if a==swapB and b==swapA else 2 else: return False #meaning more than 1 mismatch appeared return flagOK==1 #if flag=0 (no swap) or flag=2 (swap but letters dont match i.e: A=abcaa and B=abcbb) return False
buddy-strings
Easy, well commented Python 🐍 solution
InjySarhan
1
221
buddy strings
859
0.291
Easy
13,968
https://leetcode.com/problems/buddy-strings/discuss/1277027/Easy-Python-Solution(98.13)
class Solution: def buddyStrings(self, a: str, b: str) -> bool: if(len(a)!=len(b) or set(a)!=set(b)): return False if a==b: return False if len(set(a))==len(a) else True c=0 a=list(a) for i in range(len(a)): if(a[i]==b[i]): continue elif(a[i]!=b[i]) and c==0: s=i c+=1 else: a[i],a[s]=a[s],a[i] break return "".join(a)==b and c==1
buddy-strings
Easy Python Solution(98.13%)
Sneh17029
1
516
buddy strings
859
0.291
Easy
13,969
https://leetcode.com/problems/buddy-strings/discuss/2719709/Python-Simple-O(N)-Solution
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: if (len(s) != len(goal)): return False if (len(s) <= 1): return False if (s == goal) and len(set(s)) < len(s): return True diff = [] for i in range(len(s)): if s[i] != goal[i]: diff.append(i) if len(diff) != 2: return False return s[diff[0]] == goal[diff[1]] and s[diff[1]] == goal[diff[0]]
buddy-strings
Python Simple O(N) Solution
wyatt-h
0
16
buddy strings
859
0.291
Easy
13,970
https://leetcode.com/problems/buddy-strings/discuss/2619817/python-3-soulution-explained
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: n1=len(s) n2=len(goal) if n1!=n2: #if length is not equal we cannot make them the same with interchange return False d=defaultdict(list) mx =0 #max count of individual cnt=defaultdict(int) for i in range(n1): cnt[s[i]]+=1 if cnt[s[i]]>mx: mx=cnt[s[i]] # maximum times acharacter occurs in s d[i]=[s[i],goal[i]] #store value of both strings at an index count=0 dif=[] for k in d: a=d[k][0] #letter at index k of s b=d[k][1] #letter at index k of s if a!=b: count+=1 dif.append(k) if count>2: # only one interchange is allowed return False if count==1: return False #one index at has unmatched value , can never be interchanged if count==0: if mx >=2: #s='aa' goal='aa' return True return False #s='ab' goal='ab' if d[dif[0]][0]==d[dif[1]][1] and d[dif[1]][0]==d[dif[0]][1]: #if 2 values are at wrong index check if there interchange would make the strings same return True return False
buddy-strings
python 3 soulution explained
abhayCodes
0
34
buddy strings
859
0.291
Easy
13,971
https://leetcode.com/problems/buddy-strings/discuss/2424897/Python3-Solution-oror-If-Loops-oror-98-Fast-oror-Understandable
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: if len(s)!=len(goal): return False if s==goal: return len(s)-len(set(s))>=1 new=[] for i in range(len(s)): if s[i]!=goal[i]: new.append(i) if len(new)>2: return False if len(new)!=2: return False if s[new[0]]==goal[new[1]] and s[new[1]]==goal[new[0]]: return True return False
buddy-strings
Python3 Solution || If Loops || 98% Fast || Understandable
shashank_shashi
0
73
buddy strings
859
0.291
Easy
13,972
https://leetcode.com/problems/buddy-strings/discuss/2319827/Python-easy-explanation
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: c=0 l=len(s) if len(goal)!=l: # len of s and goal shall be same return False set_s=set() set_g=set() for i in range(l): if s[i]!=goal[i]: set_s.add(goal[i]) set_g.add(s[i]) c+=1 if (c>2) | (set_s!=set_g): # check for more than 2 mismatches return False if (c==0) &amp; (l==len(set(s))): # if there is no mismatch, check if there are repeated characters in s, repeated characters can be used for swapping return False return True
buddy-strings
Python easy explanation
sunakshi132
0
128
buddy strings
859
0.291
Easy
13,973
https://leetcode.com/problems/buddy-strings/discuss/2143733/Short-O(n)O(n)
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: if len(s) != len(goal): return False hs = set(s) d = [i for i in range(len(s)) if s[i] != goal[i]] return len(d) == 0 and len(hs) < len(s) \ or len(d) == 2 and s[d[0]] == goal[d[1]] and s[d[1]] == goal[d[0]]
buddy-strings
Short O(n)/O(n)
dima62
0
81
buddy strings
859
0.291
Easy
13,974
https://leetcode.com/problems/buddy-strings/discuss/2107100/python-3-oror-simple-solution-oror-O(n)O(1)
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: if len(s) != len(goal): return False if s == goal: return len(goal) != len(set(goal)) different = [] for i, (c1, c2) in enumerate(zip(s, goal)): if c1 != c2: different.append(i) if len(different) > 2: return False if len(different) == 1: return False i, j = different return s[i] == goal[j] and s[j] == goal[i]
buddy-strings
python 3 || simple solution || O(n)/O(1)
dereky4
0
143
buddy strings
859
0.291
Easy
13,975
https://leetcode.com/problems/buddy-strings/discuss/1906686/Python3-or-O(n)-Space%2BTime
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: diff=0 l=[] n=len(s) k=len(goal) if n!=k: return False hmap={} for i in range(n): if s[i]!=goal[i]: diff+=1 l.append(i) if s[i] not in hmap: hmap[s[i]]=1 else: hmap[s[i]]+=1 if diff==0: for j in hmap.values(): if j>1: return True return False elif diff==2: ind1,ind2=l if s[ind1]==goal[ind2] and s[ind2]==goal[ind1]: return True else: return False else: return False
buddy-strings
[Python3] | O(n) Space+Time
swapnilsingh421
0
36
buddy strings
859
0.291
Easy
13,976
https://leetcode.com/problems/buddy-strings/discuss/1339909/Just-store-all-the-mismatches-in-a-list...
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: # if they are equal, at least one char has fre > 1 if s == goal: return max(Counter(s).values()) > 1 mismatch = list() # store the pairs which are mismatched in a list, [(a,b) , (b,a)] res = 0 if len(s) != len(goal): return False for sc,gc in zip(s,goal): if sc != gc: mismatch.append([sc,gc]) # better to short circuit cause O(N) space rn if len(mismatch) != 2 : return False # nest him for O(1) if mismatch[0] == mismatch[1][::-1]: return True # otherwise if they are unequal cant do anything if s != goal: return False
buddy-strings
Just store all the mismatches in a list...
yozaam
0
89
buddy strings
859
0.291
Easy
13,977
https://leetcode.com/problems/buddy-strings/discuss/1292799/Python%3A-Break-down-in-3-subproblems-and-solving-each-one.
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: # Case 1. Impossible to swap if len(s) != len(goal): return False # Case 2. Strings equal, check if one char dup if s == goal: return len(set(s)) < len(s) # Case 3. Strings not equal, find differences else: diff = [] # Keeping track of the places where chars are different for i, char in enumerate(goal): if char != s[i]: diff.append(i) # record difference if len(diff) != 2: return False # if not exactly one swap then we failed condition else: # otherwise just compare the swap l_s = list(s) #strings are immutable so I created a list l_s[diff[0]] = s[diff[1]] # Swap first mismatching char with the last one l_s[diff[1]] = s[diff[0]] # Swap last mismatching char with the first one return ''.join(l_s) == goal # Return if the result is equal
buddy-strings
Python: Break down in 3 subproblems & solving each one.
antonmdv
0
114
buddy strings
859
0.291
Easy
13,978
https://leetcode.com/problems/buddy-strings/discuss/972676/Python-Simple
class Solution: def buddyStrings(self, A: str, B: str) -> bool: # If lenghts are not equal, they are not buddy, as we cannot add chars if len(A) != len(B): return False mismatches = list() for i in range(0, len(A)): # Early exit in case we already have violated constraint. if len(mismatches) > 2: return False if A[i] != B[i]: mismatches.append((A[i], B[i])) if len(mismatches) == 2: # Make sure revert of second match first or can also be vice versa. return mismatches[0] == mismatches[1][::-1] if len(mismatches) == 0: # Make sure there are duplicates if arrays are exactly same. return len(A) - len(set(A)) != 0 return False
buddy-strings
Python Simple
shruti98932
0
201
buddy strings
859
0.291
Easy
13,979
https://leetcode.com/problems/buddy-strings/discuss/759491/Python-3-Simple-Solution.-Beats-98.86
class Solution: def buddyStrings(self, A: str, B: str) -> bool: if len(A) != len(B): return False a_mis_loc = [] for i in range(len(A)): if A[i] != B[i]: a_mis_loc.append(i) if len(a_mis_loc) == 2: A = list(A) A[a_mis_loc[0]], A[a_mis_loc[1]] = A[a_mis_loc[1]], A[a_mis_loc[0]] A = ''.join(A) if A == B: return True elif len(a_mis_loc) == 0 and A == B and len(A) > len(set(A)): return True else: return False
buddy-strings
Python 3 Simple Solution. Beats 98.86%
Renegade9819
0
244
buddy strings
859
0.291
Easy
13,980
https://leetcode.com/problems/buddy-strings/discuss/456019/Python3-super-simple-solution-using-a-hash-table-and-a-for()-loop
class Solution: def buddyStrings(self, A: str, B: str) -> bool: if len(A) != len(B): return False ht = {} for i in range(len(A)): if A[i] != B[i]: ht[i] = A[i] if len(ht) == 2: i,j=ht.keys() A = list(A) A[i],A[j]=A[j],A[i] return "".join(A) == B elif len(ht) == 0 and A == B and len(A) > len(set(A)): return True else: return False
buddy-strings
Python3 super simple solution using a hash table and a for() loop
jb07
0
168
buddy strings
859
0.291
Easy
13,981
https://leetcode.com/problems/buddy-strings/discuss/381785/Solution-in-Python-3-(beats-~98)-(six-lines)
class Solution: def buddyStrings(self, A: str, B: str) -> bool: C, A, B = [i for i in range(len(A)) if A[i] != B[i]], list(A), list(B) if not C and len(A) == len(B): for i in A: if A.count(i) > 1: return True elif len(C) == 2 and A[C[0]] == B[C[1]] and A[C[1]] == B[C[0]]: return True return False - Junaid Mansuri (LeetCode ID)@hotmail.com
buddy-strings
Solution in Python 3 (beats ~98%) (six lines)
junaidmansuri
0
632
buddy strings
859
0.291
Easy
13,982
https://leetcode.com/problems/buddy-strings/discuss/301833/Python3-Two-pointers
class Solution: def buddyStrings(self, A: str, B: str) -> bool: a=list(A) b=list(B) if len(A)!=len(B): return False if A==B and len(set(A))==len(A): return False start=0 pointer=start+1 while start<len(A): if A[start]==B[start]: start+=1 else: while A[start]!=B[pointer] and pointer<len(A)-1: pointer+=1 if A[start]==B[pointer] and B[start]==A[pointer]: a[start],a[pointer]=a[pointer],a[start] break return a==b
buddy-strings
Python3 Two pointers
JasperZhou
0
203
buddy strings
859
0.291
Easy
13,983
https://leetcode.com/problems/buddy-strings/discuss/1275559/Python3-solution-memory-usage-beats-90-users
class Solution: def buddyStrings(self, s: str, goal: str) -> bool: if len(s) != len(goal): return False l = [] for i in range(len(s)): if s[i] != goal[i]: l.append(i) return (len(l) == 2 and s[l[0]] == goal[l[1]] and s[l[1]] == goal[l[0]]) or (len(l) == 0 and max(Counter(s).values()) > 1)
buddy-strings
Python3 solution memory usage beats 90% users
EklavyaJoshi
-1
34
buddy strings
859
0.291
Easy
13,984
https://leetcode.com/problems/lemonade-change/discuss/1260496/Python-3-Easy-to-understand-Better-than-95
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: change5=0 change10=0 change20=0 for i in range(len(bills)): if bills[i]==5: change5+=1 elif bills[i]==10: change10+=1 change5-=1 elif bills[i]==20: if change10>0 : change5-=1 change10-=1 else: change5-=3 change20+=1 if change5<0 or change10<0 or change20<0: return False return True
lemonade-change
Python 3 Easy-to-understand Better than 95%
mk_mohtashim
4
447
lemonade change
860
0.528
Easy
13,985
https://leetcode.com/problems/lemonade-change/discuss/2187554/Python3-O(n)-oror-O(1)-Runtime%3A-1159ms-49.65-Memory%3A-18mb-49.96
class Solution: # O(n) || O(1) # Runtime: 1159ms 49.65% Memory: 18mb 49.96% def lemonadeChange(self, bills: List[int]) -> bool: fiveBills, tenBills = 0, 0 for i in bills: if i == 5: fiveBills += 1 elif i == 10: tenBills += 1 fiveBills -= 1 elif tenBills > 0: tenBills -= 1 fiveBills -= 1 else: fiveBills -= 3 if fiveBills < 0: return False return True
lemonade-change
Python3 O(n) || O(1) # Runtime: 1159ms 49.65% Memory: 18mb 49.96%
arshergon
2
156
lemonade change
860
0.528
Easy
13,986
https://leetcode.com/problems/lemonade-change/discuss/1171648/Python3-simple-solution-using-two-approaches
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: d = {5:0,10:0,20:0} for i in range(len(bills)): if bills[i] == 5: d[5] += 1 if bills[i] == 10: if d[5] >= 1: d[5] -= 1 d[10] += 1 else: return False if bills[i] == 20: if (d[5] >= 1 and d[10] >= 1): d[5] -= 1 d[10] -= 1 elif d[5] >= 3: d[5] -= 3 else: return False return True
lemonade-change
Python3 simple solution using two approaches
EklavyaJoshi
2
144
lemonade change
860
0.528
Easy
13,987
https://leetcode.com/problems/lemonade-change/discuss/1171648/Python3-simple-solution-using-two-approaches
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: _5 = 0 _10 = 0 for i in bills: if i == 5: _5 += 1 elif i == 10: if _5 >= 1: _5 -= 1 _10 += 1 else: return False else: if _5 >= 1 and _10 >= 1: _5 -= 1 _10 -= 1 elif _5 >= 3: _5 -= 3 else: return False return True
lemonade-change
Python3 simple solution using two approaches
EklavyaJoshi
2
144
lemonade change
860
0.528
Easy
13,988
https://leetcode.com/problems/lemonade-change/discuss/382679/Solution-in-Python-3
class Solution: def lemonadeChange(self, b: List[int]) -> bool: L, B = len(b), {5:0, 10:0, 20:0} for i in range(L): if b[i] == 10: if B[5] == 0: return False else: B[5] -= 1 elif b[i] == 20: if B[10] != 0 and B[5] != 0: B[5], B[10] = B[5] - 1, B[10] - 1 elif B[5] >= 3: B[5] -= 3 else: return False B[b[i]] += 1 return True - Junaid Mansuri (LeetCode ID)@hotmail.com
lemonade-change
Solution in Python 3
junaidmansuri
1
319
lemonade change
860
0.528
Easy
13,989
https://leetcode.com/problems/lemonade-change/discuss/2828971/PYTHON3-BEAT-90-EASY-TO-UNDERSTAND
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: count_5=0 count_10=0 for i in range(0,len(bills)): if count_5<0 or count_10<0: return False if bills[i]==5: count_5+=1 elif bills[i]==10: count_10+=1 count_5-=1 elif bills[i]==20 and count_10>0: count_10-=1 count_5-=1 elif bills[i]==20 and count_10==0: count_5-=3 if count_5<0 or count_10<0: return False return True
lemonade-change
PYTHON3 - BEAT 90% - EASY TO UNDERSTAND
onggiaphuoc2004
0
3
lemonade change
860
0.528
Easy
13,990
https://leetcode.com/problems/lemonade-change/discuss/2760488/Python-or-Simple-greedy-solution-or-O(n)
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: change = {5: 0, 10: 0} for b in bills: if b == 5: change[5] += 1 elif b == 10 and change[5] > 0: change[5] -= 1 change[10] += 1 elif b == 20: if change[5] > 0 and change[10] > 0: change[5] -= 1 change[10] -= 1 elif change[5] > 2 and change[10] == 0: change[5] -= 3 else: return False else: return False return True
lemonade-change
Python | Simple greedy solution | O(n)
LordVader1
0
8
lemonade change
860
0.528
Easy
13,991
https://leetcode.com/problems/lemonade-change/discuss/2685389/Lemonade-Change-or-Full-explaination-with-comments-or-Python-or-100-efficient-solution
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: # we consider all notes here #l[0] stores $5 notes #l[1] stores $10 notes #l[2] stores $20 notes l=[0]*3 for i in bills: if i==5: # if customer gives $5 note l[0]+=1 # then l[0]+=1 (increase the no of $5 notes) elif i==10: # if customer gives $10 note then seller has to return total $5 l[1]+=1 # then l[1]+=1 (increase the no of $10 notes) if l[0]>=1: # check if seller has $5 note to return l[0]-=1 # then l[0]-=1 (decrease the no of $5 notes) else: return False # otherwise return false elif i==20: # if customer gives $20 note then seller has to return total $15 l[2]+=1 # then l[2]+=1 (increase the no of $20 notes) # total 2 combination possible : # 1 combination $10 + $5 = $15 # 2 combination $5 + $5 + $5 = $15 if l[1]>=1 and l[0]>=1: # 1 combination l[1]-=1 # decrease 1 $10 note l[0]-=1 # decrease 1 $5 note ($10 + $5 = $15) elif l[0]>=3: # 2 combination $5 + $5 + $5 = $15 l[0]-=3 # decrease 3 $5 note ($5 + $5 + $5 = $15) else: return False # otherwise return false return True
lemonade-change
Lemonade Change | Full explaination with comments | Python | 100% efficient solution
saptarishimondal
0
4
lemonade change
860
0.528
Easy
13,992
https://leetcode.com/problems/lemonade-change/discuss/2406447/Python-97.19-faster-or-Simplest-solution-with-explanation-or-Beg-to-Adv-or-Greedy
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: count5 = 0 # taking counter for $5 count10 = 0 # taking counter for $10 for b in bills: # treversing the list of bills. if b == 5: count5+=1 # if the bill is 5, incresing the 5 counter. elif b == 10: if count5 == 0: # if the bill is 10 &amp; we dont have change to return, then its false. return False count10+=1 # increasing the 10 counter count5-=1 # decreasing 5 counter as we`ll give 5 as change. else: # if the bill is of $20 if (count5>=1 and count10>=1):# checking if we have enough change to return count5-=1 # if its a $20 , then $5 as change and count10-=1 # one $10 elif count5>=3: # fi we dont have $10 as change, though we have three $3. count5-=3 # decresing the $3 counter. else: return False return True ``` ***Found helpful, Do upvote !!***
lemonade-change
Python 97.19% faster | Simplest solution with explanation | Beg to Adv | Greedy
rlakshay14
0
103
lemonade change
860
0.528
Easy
13,993
https://leetcode.com/problems/lemonade-change/discuss/2352179/Python-straight-forward
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: change = {5:0,10:0} for i in bills: if i==5: change[5]+=1 elif i==10: if change[5]>0: change[5]-=1 change[10]+=1 else: return False else: if (change[10]>0) &amp; (change[5]>0): change[10]-=1 change[5]-=1 elif change[5]>=3: change[5]-=3 else: return False return True
lemonade-change
Python straight forward
sunakshi132
0
48
lemonade change
860
0.528
Easy
13,994
https://leetcode.com/problems/lemonade-change/discuss/2161802/easy-understanding-solution-using-dictionaries
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: d={} d[5]=0 d[10]=0 d[20]=0 for i in bills: print(d) if i==5: d[5]+=1 elif i==10: d[10]+=1 if d[5]>=1: d[5]-=1 else: return 0 else: if d[5]>=3 and d[10]<1: d[5]-=3 elif d[5]>=1 and d[10]>=1: d[10]-=1 d[5]-=1 else: return 0 return 1
lemonade-change
easy understanding solution using dictionaries
captain_sathvik
0
31
lemonade change
860
0.528
Easy
13,995
https://leetcode.com/problems/lemonade-change/discuss/1834287/Simple-Python-Solution-oror-90-Faster-oror-Memory-less-than-95
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: five=0 ; ten=0 for i in range(len(bills)): if bills[i]==5: five+=1 elif bills[i]==10: ten+=1 ; five-=1 elif ten>0: five-=1 ; ten-=1 else: five-=3 if five<0: return False return True
lemonade-change
Simple Python Solution || 90% Faster || Memory less than 95%
Taha-C
0
93
lemonade change
860
0.528
Easy
13,996
https://leetcode.com/problems/lemonade-change/discuss/1169310/Python3-Greedy-Solution-Intuition
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: cash, cost, hmap = 0, 5, {5:0, 10:0, 20:0} for i, c in enumerate(bills): if c == cost: hmap[c] += 1 elif c > cost: change = c - cost # To give change, we have to greedily choose the denominations hmap = {k:v for k, v in sorted(hmap.items(), key=lambda x:x[0], reverse=True)} for k, v in hmap.items(): if change and v > 0: q, r = divmod(change, k) # Also here, we can only account for what we have so using min() - greedy intuiton min_take = min(v, q) hmap[k] -= min_take change -= min_take * k # Check if change can be given, then accept incoming bill if change == 0: hmap[c] += 1 else: return False return True
lemonade-change
Python3 Greedy Solution / Intuition
cppygod
0
105
lemonade change
860
0.528
Easy
13,997
https://leetcode.com/problems/lemonade-change/discuss/1140460/Simple-Python3-Solution-92.5-faster
class Solution: def lemonadeChange(self, bills: List[int]) -> bool: keep = {5:0, 10:0} #dictionary representing count of $5 and $10 bills for bill in bills: if bill==5: keep[5]+=1 #No change to give, just increase the count of $5 bills elif bill==10 and keep[5]==0: return False #A $5 bill to be given, but no $5 bill in keep elif bill==10 and keep[5]>0: keep[5]-=1 #A $5 bill can be given, so decrease the count of $5 bills keep[10]+=1 #Got a $10 bill, increase the count of $10 bills elif bill==20 and keep[5]>=1 and keep[10]>=1: keep[5]-=1 #If we have a $10 bill and $5 bill, we use them at first keep[10]-=1 #Decrease the counts of $10 bills and $5 bills by one elif bill==20 and keep[5]>=3: keep[5]-=3 #If we don't have any $10 bills, we have to use 3 $5 bills #Decrease the count of $5 bills by three else: return False #Not enough bills to give change, return False #print(keep[5], keep[10]) return True #All customers got change, so return True
lemonade-change
Simple Python3 Solution, 92.5% faster
bPapan
0
70
lemonade change
860
0.528
Easy
13,998
https://leetcode.com/problems/lemonade-change/discuss/543437/Python-easy-solution-O(n)-120-ms-12MB-O(n)
class Solution(object): def lemonadeChange(self, bills): """ :type bills: List[int] :rtype: bool """ previous_5 = 0 previous_10 = 0 price = 5 for bill in bills: if bill - price == 5: previous_5 -= 1 previous_10 += 1 elif bill - price == 15: previous_5 -= 1 if previous_10 > 0: previous_10 -= 1 else: previous_5 -= 2 else: previous_5 += 1 if previous_5 < 0: return False return True
lemonade-change
Python easy solution O(n) 120 ms, 12MB, O(n)
hemina
0
213
lemonade change
860
0.528
Easy
13,999