text
stringlengths
49
983k
#include <bits/stdc++.h> using namespace std; int n; int idxs[500500]; long long vals[500500]; long long l[500500], r[500500]; bool cmp_idx(int a, int b) { return vals[a] < vals[b]; } void rem(int idx) { l[r[idx]] = l[idx]; r[l[idx]] = r[idx]; } int main() { while (cin >> n) { for (int i = 1; i <= n; ++i) { cin >> vals[i]; idxs[i] = i; l[i] = i - 1; r[i] = i + 1; } vals[0] = vals[n + 1] = 0; sort(idxs + 1, idxs + n + 1, cmp_idx); int l_idx = 1, r_idx = n; long long ans = 0; for (int i = 1; i <= n; ++i) { int idx = idxs[i]; ans += min(vals[l[idx]], vals[r[idx]]); if (l_idx == idx) { l_idx = r[idx]; } else if (r_idx == idx) { r_idx = l[idx]; } else { rem(idx); } } cout << ans << '\n'; } return 0; }
#include <bits/stdc++.h> using namespace std; const long long inf = 1000000000ll; const long long inf64 = inf * inf; const double pi = acos(-1.0); long long Abs(long long x) { return (x >= 0 ? x : -x); } bool solve() { int n; cin >> n; vector<int> a(n), l(n, -1), r(n, -1); vector<bool> can(n, 1); vector<pair<int, int> > b(n); for (int i(0); i < n; i++) cin >> a[i], b[i] = make_pair(a[i], i); sort((b).begin(), (b).end()); for (int i(1); i < n; i++) l[i] = i - 1; for (int i(0); i < n - 1; i++) r[i] = i + 1; int u, d; d = 0, u = n - 1; long long ans = 0; for (int i(0); i < n - 2; i++) { if (b[i].second == d) ans += b[i].first, d = r[d]; else if (b[i].second == u) ans += b[i].first, u = l[u]; else { ans += min(a[l[b[i].second]], a[r[b[i].second]]); r[l[b[i].second]] = r[b[i].second]; l[r[b[i].second]] = l[b[i].second]; } } cout << ans << '\n'; return true; } int main() { solve(); return 0; }
#include <bits/stdc++.h> using namespace std; vector<int> v; int main() { long long n, ans = 0; cin >> n; for (int i = 0; i < n; i++) { int k, s = v.size(); cin >> k; while (s > 1 && v[s - 1] <= k && v[s - 1] <= v[s - 2]) ans += min(k, v[s - 2]), v.pop_back(), s--; v.push_back(k); } sort(v.begin(), v.end()); for (int i = 0; i < (int)v.size() - 2; i++) ans += v[i]; cout << ans << endl; }
#include <bits/stdc++.h> using namespace std; long long int ans; long long int s[1000000]; int main() { long long int x; int n, i, t = -1; scanf("%d", &n); ans = 0; for (i = 0; i < n; i++) { scanf("%lld", &x); while (t > 0 && s[t] <= s[t - 1] && s[t] <= x) { ans = ans + min(s[t - 1], x); t--; } t++; s[t] = x; } sort(s, s + t + 1); for (i = 0; i < t - 1; i++) ans = ans + s[i]; printf("%lld\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 5e5 + 3; int S[N], tp; int main() { int n; long long ans = 0; scanf("%d", &n); for (register int i = 1; i <= n; i++) { int x; scanf("%d", &x); while (tp >= 2 && S[tp - 1] >= S[tp] && x >= S[tp]) { ans += min(S[tp - 1], x); --tp; } S[++tp] = x; } sort(S + 1, S + tp + 1); for (register int i = 1; i <= tp - 2; i++) ans += S[i]; printf("%lld", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 5e5 + 5; int n; long long res; int a[N]; stack<int> s; priority_queue<int, vector<int>, greater<int> > q; int main(void) { scanf("%d", &n); for (register int i = 1; i <= n; ++i) { scanf("%d", a + i); while (s.size() >= 2) { int x = s.top(); s.pop(); int y = s.top(); if (x <= ((y) < (a[i]) ? (y) : (a[i]))) res += ((y) < (a[i]) ? (y) : (a[i])); else { s.push(x); break; } } s.push(a[i]); } while (!s.empty()) { q.push(s.top()); s.pop(); } while (q.size() > 2) { res += q.top(); q.pop(); } printf("%lld\n", res); return 0; }
#include <bits/stdc++.h> #pragma comment(linker, "/STACK:65000000") using namespace std; int n; pair<int, int> mas[500500]; set<pair<int, int> > st; int main(int argc, const char* argv[]) { scanf("%d", &n); for (int i = 0; i < n; ++i) { scanf("%d", &mas[i].first); mas[i].second = i; st.insert(pair<int, int>(mas[i].second, mas[i].first)); } sort(mas, mas + n); long long answ = 0; int bound = 0; for (int i = 0; i < n - 2; ++i) { answ += (mas[i].first - bound) * (long long)(n - 2 - i); bound = mas[i].first; pair<int, int> p(mas[i].second, mas[i].first); set<pair<int, int> >::iterator it = st.find(p); if (it != st.begin()) { ++it; int ad = 0; if (it != st.end()) ad = it->second - bound; --it; --it; ad = min(ad, it->second - bound); answ += ad; ++it; } st.erase(it); } cout << answ << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int MAX_SIZE = 500000; int data[MAX_SIZE + 10], n; int s[MAX_SIZE + 10], top; int main() { scanf("%d", &n); for (int i = 1; i <= n; i++) scanf("%d", data + i); long long ans = 0; for (int i = 1; i <= n; i++) { while (top > 1 && s[top - 2] >= s[top - 1] && data[i] >= s[top - 1]) { ans += min(s[top - 2], data[i]); --top; } s[top++] = data[i]; } sort(s, s + top); for (int i = 0; i < top - 2; i++) ans += s[i]; printf( "%I64d" "\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const long long mod = 1e9 + 7; const long long INF = 4e18; const int inf = 2e9; const int N = 5e5 + 5; int gcd(int a, int b) { return b ? gcd(b, a % b) : a; } int lcm(int a, int b) { return a * b / gcd(a, b); } int ne[N], pr[N], a[N]; queue<int> q; bool done[N]; void check(int i) { if (done[i]) return; if (a[pr[i]] >= a[i] && a[i] <= a[ne[i]]) { q.push(i); done[i] = 1; } } int main(void) { int n, i; scanf("%d", &n); for (i = 1; i <= n; ++i) { scanf("%d", &a[i]); pr[i] = i - 1; ne[i] = i + 1; } ne[0] = 1; pr[n + 1] = n; for (i = 1; i <= n; ++i) check(i); long long ans = 0; while (q.size()) { int now = q.front(); q.pop(); int next = ne[now]; int prev = pr[now]; ne[prev] = next; pr[next] = prev; ans += min(a[next], a[prev]); check(next); check(prev); } int now = ne[0]; while (now <= n) { ans += min(a[pr[now]], a[ne[now]]); now = ne[now]; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int MN = 500111; int a[MN], res[MN], cur, left_[MN], right_[MN], st[MN], n; int it[MN * 3]; int better(int x, int y) { if (!x) return y; if (!y) return x; if (a[x] > a[y]) return x; else return y; } void buildTree(int i, int l, int r) { if (l == r) { it[i] = l; return; } int mid = (l + r) >> 1; buildTree(((i) << 1), l, mid); buildTree((((i) << 1) + 1), mid + 1, r); it[i] = better(it[((i) << 1)], it[(((i) << 1) + 1)]); } int getMin(int i, int l, int r, int u, int v) { if (v < l || r < u) return 0; if (u <= l && r <= v) return it[i]; int res = u; int mid = (l + r) >> 1; res = better(getMin(((i) << 1), l, mid, u, v), res); res = better(getMin((((i) << 1) + 1), mid + 1, r, u, v), res); return res; } void init() { int top = 0; st[0] = 0; for (int i = (1), _b = (n); i <= _b; i++) { while (top && a[st[top]] < a[i]) --top; left_[i] = st[top]; st[++top] = i; } top = 0; st[0] = n + 1; for (int i = (n), _b = (1); i >= _b; i--) { while (top && a[st[top]] < a[i]) --top; right_[i] = st[top]; st[++top] = i; } } void solve(int l, int r) { if (l + 1 >= r) return; if (a[l] <= a[r]) { int u = right_[l]; if (u == r) { u = getMin(1, 1, n, l + 1, r - 1); } res[cur--] = u; solve(l, u); solve(u, r); } else { int u = left_[r]; if (u == l) { u = getMin(1, 1, n, l + 1, r - 1); } res[cur--] = u; solve(l, u); solve(u, r); } } int main() { ios ::sync_with_stdio(false); while (cin >> n) { for (int i = (1), _b = (n); i <= _b; i++) cin >> a[i]; init(); buildTree(1, 1, n); cur = n - 2; solve(1, n); set<int> s; for (int i = (1), _b = (n); i <= _b; i++) s.insert(i); long long sum = 0; for (int turn = (1), _b = (n - 2); turn <= _b; turn++) { int u = res[turn]; s.erase(u); __typeof(s.begin()) next = s.lower_bound(u), prev = next; --prev; sum += min(a[*next], a[*prev]); } cout << sum << endl; } return 0; }
#include <bits/stdc++.h> using namespace std; const int inf = 1e9, mod = 1e9 + 7; const int N = 5e5 + 5; set<pair<int, int> > S; vector<pair<int, int> > v; int h[N], a[N], x, n; long long ans; int main() { scanf("%d", &n); for (int i = 1; i <= n; i++) { scanf("%d", &a[i]); S.insert(make_pair(i, a[i])); v.push_back(make_pair(a[i], i)); } set<pair<int, int> >::iterator it, it2, it3; sort(v.begin(), v.end()); for (__typeof(v.begin()) c = v.begin(); c != v.end(); c++) { int index = c->second; if (index == 1 || index == n) continue; it2 = S.lower_bound(make_pair(index, 0)); it = it2; it3 = it2; it--; it3++; int cost = min(it->second, it3->second); if (it2->second > cost) continue; ans += cost; S.erase(it2); } vector<int> v2; for (__typeof(S.begin()) it = S.begin(); it != S.end(); it++) v2.push_back(it->second); sort(v2.begin(), v2.end()); for (int i = 0; i <= (int)v2.size() - 3; i++) ans += v2[i]; cout << ans << '\n'; return 0; }
#include <bits/stdc++.h> using namespace std; long long d[500050]; int chk[500050]; vector<int> checked; int it[1048577]; int IT_MAX = 524288; long long ANS = 0; void update(int node, int val) { it[node] = node - IT_MAX + 1; while (node > 1) { node /= 2; if (d[it[2 * node]] > d[it[2 * node + 1]]) it[node] = it[2 * node]; else it[node] = it[2 * node + 1]; } return; } int get_MAX(int n1, int n2) { int t = -1; if (n1 == n2) return it[n1]; if (n1 % 2 == 1) { t = it[n1]; n1++; } if (n1 == n2) { if (t == -1) return it[n1]; else return (d[t] > d[it[n1]]) ? t : it[n1]; } if (n2 % 2 == 0) { if (t == -1) t = it[n2]; else t = (d[t] > d[it[n2]]) ? t : it[n2]; n2--; } int t2 = get_MAX(n1 / 2, n2 / 2); if (t == -1) return t2; else return (d[t] > d[t2]) ? t : t2; } void get_ans(int n1, int n2) { if (n2 == n1 + 1) return; ANS += min(d[n1], d[n2]); int n3 = get_MAX(n1 + IT_MAX, n2 + IT_MAX - 2); get_ans(n1, n3); get_ans(n3, n2); return; } int main() { int N, i; scanf("%d", &N); for (i = 1; i <= N; i++) { scanf("%lld", &d[i]); update(i - 1 + IT_MAX, d[i]); } chk[1] = chk[N] = 1; int st = 1, en = N, mi; while (st < en) { if (d[st] > d[en]) { mi = en - 1; while (d[mi] <= d[en]) { mi--; if (st == mi) break; } if (st == mi) break; else { chk[mi] = 1; ANS += d[en]; en = mi; } } else { mi = st + 1; while (d[mi] <= d[st]) { mi++; if (en == mi) break; } if (en == mi) break; else { chk[mi] = 1; ANS += d[st]; st = mi; } } } for (i = 1; i <= N; i++) if (chk[i] == 1) checked.push_back(i); for (i = 0; i < checked.size() - 1; i++) { get_ans(checked[i], checked[i + 1]); } printf("%lld", ANS); return 0; }
#include <bits/stdc++.h> int num[500000], am; long long int ans; int min(int i1, int i2) { if (i1 < i2) return i1; return i2; } int max(int i1, int i2) { if (i1 > i2) return i1; return i2; } void read() { scanf("%d", &num[am]); am++; while (am > 2 && (num[am - 2] <= num[am - 3] && num[am - 2] <= num[am - 1])) { ans += min(num[am - 3], num[am - 1]); num[am - 2] = num[am - 1]; am--; } } void solve(int n) { int i, j, k, l; ans = 0; if (n <= 2) { if (n == 1) scanf("%d", &i); if (n == 2) scanf("%d%d", &i, &j); printf("0\n"); return; } am = 2; scanf("%d%d", &num[0], &num[1]); for (i = 0; i < n - 2; i++) read(); if (n <= 2) { printf("%I64d\n", ans); return; } if (num[0] <= num[1] && num[am - 2] <= num[am - 1]) { for (i = 0; i < am - 2; i++) ans += num[i]; printf("%I64d\n", ans); return; } if (num[0] >= num[1] && num[am - 2] >= num[am - 1]) { for (i = 2; i < am; i++) ans += num[i]; printf("%I64d\n", ans); return; } for (i = 0; i < am; i++) ans += num[i]; l = 0; for (i = 0; i < am; i++) if (num[l] < num[i]) l = i; ans -= num[l]; ans -= max(num[l - 1], num[l + 1]); printf("%I64d\n", ans); } int main() { #pragma comment(linker, "/STACK:67108864") int n; while (scanf("%d", &n) != EOF) { solve(n); } return 0; }
#include <bits/stdc++.h> using namespace std; const int SIZE = 1 << 26; char gc[SIZE], *pgc = gc; char pc[SIZE], *ppc = pc; clock_t clk = clock(); struct flusher { flusher() { fread(gc, true, SIZE, stdin); } ~flusher() { fwrite(pc, true, ppc - pc, stdout); } } Flusher; int _Neg = 0; template <class T> void rd(T& x) { x = _Neg = 0; while (!isdigit(*pgc)) { if ((*pgc++) == '-') { _Neg = 1; } } while (isdigit(*pgc)) { x = x * 10 + *pgc++ - 48; } if (_Neg) { x = -x; } } int _Stk[233], _Top = 0; template <class T> void pt(T x, char c = '\n') { if (x < 0) { *ppc++ = '-'; x = -x; } do { _Stk[++_Top] = x % 10; x /= 10; } while (x); while (_Top) { *ppc++ = _Stk[_Top--] + 48; } *ppc++ = c; } void pts(const string& str) { int len = (int)str.size(); for (int i = 0; i <= len - 1; i++) { *ppc++ = str[i]; } *ppc++ = '\n'; } template <class T> void cmax(T& x, const T& y) { x = (x > y) ? x : y; } template <class T> void cmin(T& x, const T& y) { x = (x < y) ? x : y; } int n; const int N = 524288; int a[N]; int st[N], top; int main() { rd(n); for (int i = 1; i <= n; i++) { rd(a[i]); } int64_t ans = 0; for (int i = 1; i <= n; i++) { int t3 = a[i]; while (top >= 2) { int t2 = st[top--]; int t1 = st[top]; if (t1 >= t2 && t2 <= t3) { ans += std::min(t1, t3); } else { st[++top] = t2; break; } } st[++top] = t3; } std::sort(st + 1, st + top + 1); for (int i = 1; i <= top - 2; i++) ans += st[i]; pt(ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int MAXN = 500005; const int inf = 100000000; struct elem { long long val; int l, r; }; struct V { long long val; int ind; }; bool compare(V x, V y) { if (x.val < y.val) return true; if (x.val == y.val && x.ind < y.ind) return true; return false; } V a[MAXN]; elem L[MAXN]; int main() { int N; cin >> N; for (int i = 1; i <= N; i++) { cin >> a[i].val; a[i].ind = i; L[i].val = a[i].val; L[i].l = i - 1; L[i].r = i + 1; } int GlobalLeft = 1; int GlobalRight = N; sort(a + 1, a + N + 1, compare); long long ans = 0; a[N + 1].val = inf; int pntL = 1, pntR = 1; int Left = N; while (pntL <= N && Left > 2) { pntR = pntL; while (a[pntR].val == a[pntL].val) pntR++; int NextL = pntR; pntR--; while (pntL <= pntR && a[pntL].ind == GlobalLeft && Left > 2) { ans += L[GlobalLeft].val; GlobalLeft = L[GlobalLeft].r; pntL++; Left--; } while (pntL <= pntR && a[pntR].ind == GlobalRight && Left > 2) { ans += L[GlobalRight].val; GlobalRight = L[GlobalRight].l; pntR--; Left--; } while (pntL <= pntR && Left > 2) { ans += min(L[L[a[pntL].ind].l].val, L[L[a[pntL].ind].r].val); L[L[a[pntL].ind].l].r = L[a[pntL].ind].r; L[L[a[pntL].ind].r].l = L[a[pntL].ind].l; pntL++; Left--; } pntL = NextL; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; inline long long read() { long long X = 0, w = 1; char ch = 0; while (ch < '0' || ch > '9') { if (ch == '-') w = -1; ch = getchar(); } while (ch >= '0' && ch <= '9') X = (X << 3) + (X << 1) + ch - '0', ch = getchar(); return X * w; } const long long maxn = 1e6 + 10; long long s[maxn], top; long long ans; long long n; int main() { n = read(); for (long long i = 1; i <= n; i++) { long long x = read(); while (top > 1 && s[top - 1] >= s[top] && x >= s[top]) { ans += min(s[top - 1], x); top--; } s[++top] = x; } sort(s + 1, s + 1 + top); for (long long i = 1; i <= top - 2; i++) { ans += s[i]; } cout << ans; }
#include <bits/stdc++.h> using namespace std; struct yo { int val; int id; int next, prev; }; vector<yo> a0, a; int n, n0, x; bool operator<(yo a, yo b) { return a.val < b.val; } int main() { cin >> n; n0 = n; if (n <= 2) { cout << 0; return 0; } for (int i = 0; i < n; i++) { cin >> x; yo cur; cur.val = x; cur.id = i; cur.next = i + 1; cur.prev = i - 1; a0.push_back(cur); a.push_back(cur); } sort(a.begin(), a.end()); long long v = 0, ans = 0; for (int i = 0; i < a.size() - 2; i++) { int cur_id = a[i].id; if (a0[cur_id].prev == -1) { a0[a0[cur_id].next].prev = -1; ans += (n - 2) * (a[i].val - v); v += (a[i].val - v); } else if (a0[cur_id].next == n0) { a0[a0[cur_id].prev].next = n0; ans += (n - 2) * (a[i].val - v); v += (a[i].val - v); } else { ans += min(a0[a0[cur_id].prev].val, a0[a0[cur_id].next].val) - v; a0[a0[cur_id].next].prev = a0[cur_id].prev; a0[a0[cur_id].prev].next = a0[cur_id].next; } n--; } cout << ans; }
#include <bits/stdc++.h> using namespace std; vector<int> a; bool cmp(int i, int j) { return a[i] < a[j]; } int main() { int n; scanf("%d", &n); a.resize(n); for (int i = 0; i < n; i++) scanf("%d", &a[i]); set<int> s; for (int i = 0; i < n; i++) s.insert(i); vector<int> v; for (int i = 0; i < n; i++) v.push_back(i); sort(v.begin(), v.end(), cmp); long long ans = 0; for (int i = 0; i < n; i++) { set<int>::iterator it = s.find(v[i]), l, r; if (it == s.begin()) continue; l = r = it; l--; r++; if (r == s.end()) continue; if (a[*it] > min(a[*l], a[*r])) continue; ans += (long long)min(a[*l], a[*r]); s.erase(it); } int i; for (i = n - 1; i >= 0; i--) if (s.find(v[i]) != s.end()) break; for (i--; i >= 0; i--) if (s.find(v[i]) != s.end()) break; for (i--; i >= 0; i--) if (s.find(v[i]) != s.end()) ans += a[v[i]]; printf("%I64d", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int NMAX = 500010; int N, V[NMAX], Prev[NMAX], Next[NMAX]; long long Ans; queue<int> Q; bool Added[NMAX]; void Add(int X) { if (Added[X]) return; if (V[Prev[X]] >= V[X] && V[X] <= V[Next[X]]) { Q.push(X); Added[X] = 1; } } int main() { scanf("%i", &N); for (int i = 1; i <= N; ++i) { scanf("%i", &V[i]); Prev[i] = i - 1; Next[i] = i + 1; } Next[0] = 1; Prev[N + 1] = N; for (int i = 2; i < N; ++i) Add(i); while (!Q.empty()) { int X = Q.front(); Q.pop(); Next[Prev[X]] = Next[X]; Prev[Next[X]] = Prev[X]; Ans += min(V[Prev[X]], V[Next[X]]); Add(Prev[X]); Add(Next[X]); } for (int X = 0; X != N + 1; X = Next[X]) Ans += min(V[Prev[X]], V[Next[X]]); printf("%I64d", Ans); }
#include <bits/stdc++.h> using namespace std; int main() { cin.sync_with_stdio(0); cin.tie(0); int N; scanf(" %d", &N); vector<int> A(N); vector<pair<int, int> > ord(N); for (int i = 0; i < N; i++) { scanf(" %d", &A[i]); ord[i].first = A[i]; ord[i].second = i; } sort(begin(ord), end(ord)); vector<int> nxt(N + 1, -1), prev(N + 1, -1); for (int i = 0; i < N; i++) nxt[i] = i + 1, prev[i + 1] = i; int l = 0, r = N - 1; long long ans = 0, sub = 0; for (int i = 0; i < N - 2; i++) { if (ord[i].second == l || ord[i].second == r) { ans += 1LL * (ord[i].first - sub) * (N - 2 - i); sub = ord[i].first; if (ord[i].second == l) l = nxt[l]; else r = prev[r]; continue; } int x = prev[ord[i].second], y = nxt[ord[i].second]; ans += min(A[x], A[y]) - sub; prev[y] = x; nxt[x] = y; } printf("%lld\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int dx[] = {-1, 0, 1, 0, -1, -1, 1, 1}; const int dy[] = {0, -1, 0, 1, -1, 1, 1, -1}; template <class T> inline bool get(T& n) { char c, mul = 1; n = 0; while (!isdigit(c = getchar_unlocked()) && (c != EOF) && (c != '-')) ; if (c == EOF) return false; if (c == '-') { c = getchar_unlocked(); mul = -1; } for (; isdigit(c); c = getchar_unlocked()) n = n * 10 + c - '0'; n *= mul; return true; } inline void get(char& c) { while (isspace(c = getchar_unlocked())) ; } int n; int v[500050]; int l[500050], r[500050]; set<pair<int, int> > s; int main() { get(n); for (int(i) = 0, _ = (n); (i) < _; ++i) { get(v[i]); s.insert(make_pair(v[i], i)); l[i] = i - 1; r[i] = i + 1; } r[n - 1] = -1; long long ans = 0; int prev = 0; while ((int)s.size() > 1) { int pos = s.begin()->second; int val = s.begin()->first; s.erase(s.begin()); int left = l[pos], right = r[pos]; if (left >= 0 && right >= 0) ans += min(v[left], v[right]) - val; ans += (val - prev) * ((int)s.size() - 1); if (left >= 0) r[left] = right; if (right >= 0) l[right] = left; prev = val; } printf("%I64d\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 1000010; int a[N]; pair<int, int> p[N]; int pr[N], ne[N]; int main() { int n; scanf("%d", &n); for (int i = 0; i < n; i++) { scanf("%d", a + i); p[i] = make_pair(a[i], i); } sort(p, p + n); for (int i = 0; i < n; i++) { pr[i] = i - 1; ne[i] = i + 1; } int low = 0, high = n - 1; long long ans = 0; for (int i = 0; i < n - 2; i++) { int j = p[i].second; if (j == low) { ans += p[i].first; low = ne[low]; continue; } if (j == high) { ans += p[i].first; high = pr[high]; continue; } int x = a[pr[j]]; int y = a[ne[j]]; if (x < y) { ans += x; } else { ans += y; } pr[ne[j]] = pr[j]; ne[pr[j]] = ne[j]; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; template <class t> t lcm(t a, t b) { return ((a * b) / __gcd(a, b)); } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); ; long long ans = 0; long long n, temp; cin >> n; pair<long long, long long> ip[n], org[n]; long long prev[n], nxt[n], lcorner = 0, rcorner = n - 1; for (long long i = 0; i < n; i++) { cin >> ip[i].first; ip[i].second = i; prev[i] = i - 1; nxt[i] = i + 1; org[i] = ip[i]; } sort(ip, ip + n); for (long long i = 0; i < (n - 2); i++) { pair<long long, long long> cur = ip[i]; if (cur.second == lcorner) { lcorner = nxt[lcorner]; ans += cur.first; } else if (cur.second == rcorner) { rcorner = prev[rcorner]; ans += cur.first; } else { nxt[prev[cur.second]] = nxt[cur.second]; prev[nxt[cur.second]] = prev[cur.second]; ans += min(org[prev[cur.second]].first, org[nxt[cur.second]].first); } } cout << ans; return 0; }
#include <bits/stdc++.h> using namespace std; const long long N = 5e5 + 5; long long a[N]; signed main() { long long n; cin >> n; long long m = -1; long long ans = 0; for (int i = 1; i <= n; i++) { m++; cin >> a[m]; while (m >= 2 && a[m - 1] <= min(a[m - 2], a[m])) { ans = ans + min(a[m - 2], a[m]); a[m - 1] = a[m]; m--; } } for (int i = 1; i <= m - 1; i++) { ans = ans + min(a[i - 1], a[i + 1]); } cout << ans; }
#include <bits/stdc++.h> using namespace std; int n, a[500010], b[500010], p = 0; long long ans; int main() { scanf("%d", &n); for (int i = 1; i <= n; i++) { scanf("%d", &a[i]); while (p >= 2 && b[p - 2] >= b[p - 1] && a[i] >= b[p - 1]) ans += min(b[p - 2], a[i]), p--; b[p] = a[i]; p++; } sort(b, b + p); for (int i = 0; i <= p - 3; i++) ans += b[i]; printf("%lld", ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int A = (int)1e9, N = 528228; long long o; set<pair<int, int> > g; int i, e[2], d[2], t[2][N * 4], j, n, m, a[N]; void modi(int v, int l, int r, int g, int h) { if (l == r) { if (g) t[0][v] = h, t[1][v] = h; else t[0][v] = -A, t[1][v] = A; return; } int mid = (l + r) / 2; if (h <= mid) modi(v * 2, l, mid, g, h); else modi(v * 2 + 1, mid + 1, r, g, h); t[0][v] = max(t[0][v * 2], t[0][v * 2 + 1]); t[1][v] = min(t[1][v * 2], t[1][v * 2 + 1]); } long long get(int v, int l, int r, int _l, int _r) { if (l > r || _l > _r) return A; if (l == _l && r == _r) return t[1][v]; int mid = (l + r) / 2; return min(get(v * 2, l, mid, _l, min(_r, mid)), get(v * 2 + 1, mid + 1, r, max(_l, mid + 1), _r)); } long long _get(int v, int l, int r, int _l, int _r) { if (l > r || _l > _r) return -A; if (l == _l && r == _r) return t[0][v]; int mid = (l + r) / 2; return max(_get(v * 2, l, mid, _l, min(_r, mid)), _get(v * 2 + 1, mid + 1, r, max(_l, mid + 1), _r)); } int main() { cin >> n; for (i = 0; i < n; i++) { scanf("%d", &a[i]); g.insert(make_pair(a[i], i + 1)); modi(1, 1, n, 1, i + 1); } for (i = 0; i < n - 2; i++) { e[0] = (*g.begin()).first, e[1] = (*g.begin()).second, g.erase(*g.begin()); modi(1, 1, n, 0, e[1]); d[0] = _get(1, 1, n, 1, e[1]), d[1] = get(1, 1, n, e[1], n); if (d[0] != -A && d[1] != A) o += min(a[d[0] - 1], a[d[1] - 1]); else o += e[0]; } cout << o << "\n"; }
#include <bits/stdc++.h> using namespace std; template <typename T> inline void read(T &_x_) { _x_ = 0; bool f = false; char ch = getchar(); while (ch < '0' || ch > '9') { if (ch == '-') f = !f; ch = getchar(); } while ('0' <= ch && ch <= '9') { _x_ = _x_ * 10 + ch - '0'; ch = getchar(); } if (f) _x_ = -_x_; } const double eps = 1e-8; const int maxn = 1e5 + 7; const int mod = 1e9 + 7; const long long inf = 1e15; long long n, x, ans = 0; stack<long long> s; int main() { read(n); read(x); s.push(x); for (long long i = 2; i <= n; i++) { read(x); while (s.size() >= 2) { long long a = s.top(); s.pop(); long long b = s.top(); if (a <= b && a <= x) { ans += min(x, b); } else { s.push(a); break; } } s.push(x); } long long mi = 0, mx = 0, sum = 0; while (!s.empty()) { long long u = s.top(); s.pop(); sum += u; if (u >= mx) { mi = mx; mx = u; } else if (u > mi) mi = u; } printf("%I64d\n", ans + sum - mi - mx); return 0; }
#include <bits/stdc++.h> using namespace std; const int INF = 1000000001; const double EPS = 10e-9; int const S = 1 << 19; int n, a[S], leftlink[S], rightlink[S], decrease; pair<int, int> tree[2 * S]; pair<int, int> Min() { return tree[1]; } void Init() { tree[S] = make_pair(INF, 0); for (int i = 1; i <= (n); ++i) tree[i + S] = make_pair(a[i], i); for (int i = n + 1; i <= (S - 1); ++i) tree[S + i] = make_pair(INF, i); for (int i = S - 1; i >= (1); --i) tree[i] = min(tree[2 * i], tree[2 * i + 1]); } void Delete(int p) { for (tree[p + S] = make_pair(INF, p), p += S, p >>= 1; p; p >>= 1) tree[p] = min(tree[p * 2], tree[p * 2 + 1]); } int main() { ios_base::sync_with_stdio(false); cin >> n; for (int i = 1; i <= (n); ++i) { cin >> a[i]; leftlink[i] = i - 1; rightlink[i] = i + 1; } rightlink[n] = 0; Init(); pair<int, int> greedy; long long ans = 0; while (n) { if (n <= 2) break; greedy = Min(); Delete(greedy.second); if (!leftlink[greedy.second]) { ans += ((long long)(n - 2)) * (greedy.first - decrease); leftlink[rightlink[greedy.second]] = 0; decrease = greedy.first; --n; continue; } if (!rightlink[greedy.second]) { ans += ((long long)(n - 2)) * (greedy.first - decrease); decrease = greedy.first; rightlink[leftlink[greedy.second]] = 0; --n; continue; } leftlink[rightlink[greedy.second]] = leftlink[greedy.second]; rightlink[leftlink[greedy.second]] = rightlink[greedy.second]; ans += min(a[leftlink[greedy.second]], a[rightlink[greedy.second]]) - decrease; --n; } cout << ans; return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 5e5 + 5; int n, l[N], r[N], tl, tr, a[N], ind[N]; long long ans; inline void update(int x) { r[l[x]] = r[x]; l[r[x]] = l[x]; if (x == tl) { tl = r[x]; } else if (x == tr) { tr = l[x]; } } inline bool cmp(int x, int y) { return a[x] < a[y]; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); cin >> n; for (int i = 1; i <= n; i++) { cin >> a[i]; l[i] = i - 1, r[i] = i + 1; ind[i] = i; } sort(ind + 1, ind + n + 1, cmp); tl = 1, tr = n; for (int i = 1; i <= n; i++) { if (tl == tr || r[tl] == tr) { break; } if (ind[i] == tl || ind[i] == tr) { ans += a[ind[i]]; } else { ans += min(a[l[ind[i]]], a[r[ind[i]]]); } update(ind[i]); } cout << ans; }
#include <bits/stdc++.h> using namespace std; int main() { int n, i, num, val, pos; long long int ans = 0; vector<pair<int, int> > V; cin >> n; int arr[n], left[n], right[n]; for (i = 0; i < n; i++) { cin >> num; arr[i] = num; left[i] = i - 1; right[i] = i + 1; V.push_back(make_pair(num, i)); } sort(V.begin(), V.end()); for (i = 0; i < n; i++) { val = V[i].first; pos = V[i].second; if (pos == 0 || pos == n - 1) continue; ans += min(arr[left[pos]], arr[right[pos]]); if (arr[right[left[pos]]] < arr[right[pos]]) { right[left[pos]] = right[pos]; } if (arr[left[right[pos]]] < arr[left[pos]]) { left[right[pos]] = left[pos]; } } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int p[5 * 100010]; int pl[5 * 100010], pr[5 * 100010]; set<pair<int, int> > s; int main() { ios::sync_with_stdio(0); int n; cin >> n; for (int i = 0; i < n; ++i) { cin >> p[i]; s.insert(make_pair(p[i], i)); pr[i] = i + 1; pl[i] = i - 1; } pr[n - 1] = -1; long long ans = 0; int pos, d, prev = 0; while (s.size() > 1) { pos = s.begin()->second; d = s.begin()->first; s.erase(s.begin()); if (pl[pos] >= 0 && pr[pos] >= 0) ans += min(p[pl[pos]] - d, p[pr[pos]] - d); ans += (d - prev) * (s.size() - 1); if (pr[pos] >= 0) pl[pr[pos]] = pl[pos]; if (pl[pos] >= 0) pr[pl[pos]] = pr[pos]; prev = d; } cout << ans << "\n"; return 0; }
#include <bits/stdc++.h> using namespace std; int n; int m; int a[500000]; long long ans = 0; int main() { cin >> n; for (int i = 1; i <= n; i++) { cin >> a[++m]; while (m > 2 && a[m - 1] <= min(a[m - 2], a[m])) { ans += min(a[m - 2], a[m]); a[m - 1] = a[m]; m--; } } for (int i = 1; i < m; i++) { ans += min(a[i - 1], a[i + 1]); } cout << ans; }
#include <bits/stdc++.h> using namespace std; inline bool EQ(double a, double b) { return fabs(a - b) < 1e-9; } const int INF = 1 << 29; int n; int a[523456]; list<int>::iterator next(list<int>::iterator it, int i) { for (int j = 0; j < (i); j++) it++; return it; } list<int>::iterator prev(list<int>::iterator it, int i) { for (int j = 0; j < (i); j++) it--; return it; } int main() { scanf("%d", &n); ; for (int i = 0; i < (n); i++) scanf("%d", &a[i]); ; list<int> ls; list<int>::iterator it, mx; ls.push_back(0); for (int i = 0; i < (n); i++) ls.push_back(a[i]); ls.push_back(0); it = next(ls.begin(), 1); long long sum = 0; while (*it != 0) { if (*prev(it, 1) >= *(it) && *next(it, 1) >= *(it)) { sum += min(*prev(it, 1), *next(it, 1)); it = ls.erase(it); it--; } else { it++; } } mx = ls.begin(); for (it = ls.begin(); it != ls.end(); ++it) { if (*mx < *it) mx = it; } while (ls.size() > 4) { int me, l = 0, r = 0; me = min(*prev(mx, 1), *next(mx, 1)); if (prev(mx, 1) != ls.begin()) l = *prev(mx, 2); if (next(mx, 2) != ls.end()) r = *next(mx, 2); if (me > l && me > r) { sum += me; mx = ls.erase(mx); if (*prev(mx, 1) > *(mx)) mx--; } else { if (l > r) { sum += l; ls.erase(prev(mx, 1)); } else { sum += r; ls.erase(next(mx, 1)); } } } cout << sum << endl; return 0; }
#include <bits/stdc++.h> using namespace std; template <typename T> T POW(T B, T printf) { if (printf == 0) return 1; if (printf & 1) return B * POW(B, printf - 1); else return (POW(B, printf / 2) * POW(B, printf / 2)); } template <typename T> T BIGMOD(T b, T p, T m) { if (p == 0) return 1; else if (!(p & 1)) return (Bigmod(b, p / 2, m) * Bigmod(b, p / 2, m)) % m; else return ((b % m) * Bigmod(b, p - 1, m)) % m; } template <typename T> T DIS(T x1, T y1, T x2, T y2) { return sqrt((x1 - x2 * x1 - x2) + (y1 - y2 * y1 - y2)); } template <typename T> T ANGLE(T x1, T y1, T x2, T y2) { return atan(double(y1 - y2) / double(x1 - x2)); } template <typename T> T DIFF(T a, T b) { T d = a - b; if (d < 0) return -d; else return d; } template <typename T> T ABS(T a) { if (a < 0) return -a; else return a; } template <typename T> T GCD(T a, T b) { if (a < 0) return gcd(-a, b); if (b < 0) return gcd(a, -b); return (b == 0) ? a : gcd(b, a % b); } template <typename T> T LCM(T a, T b) { if (a < 0) return lcm(-a, b); if (b < 0) return lcm(a, -b); return a * (b / gcd(a, b)); } template <typename T> T EUCLIDE(T a, T b, T &x, T &y) { if (a < 0) { T d = euclide(-a, b, x, y); x = -x; return d; } if (b < 0) { T d = euclide(a, -b, x, y); y = -y; return d; } if (b == 0) { x = 1; y = 0; return a; } else { T d = euclide(b, a % b, x, y); T t = x; x = y; y = t - (a / b) * y; return d; } } template <typename T> T in() { char ch; T n = 0; bool ng = false; while (1) { ch = getchar(); if (ch == '-') { ng = true; ch = getchar(); break; } if (ch >= '0' && ch <= '9') break; } while (1) { n = n * 10 + (ch - '0'); ch = getchar(); if (ch < '0' || ch > '9') break; } return (ng ? -n : n); } template <typename T> long long int isLeft(T a, T b, T c) { return (c.x - a.x) * (b.y - a.y) - (b.x - a.x) * (c.y - a.y); } int Check(int N, int pos) { return (N & (1 << pos)); } int Set(int N, int pos) { return N = N | (1 << pos); } int Reset(int N, int pos) { return N = N & ~(1 << pos); } bool isVowel(char ch) { ch = toupper(ch); if (ch == 'A' || ch == 'U' || ch == 'I' || ch == 'O' || ch == 'E') return true; return false; } double DEG(double x) { return (180.0 * x) / ((2.0 * acos(0.0))); } void P_ARR(int *ar, int a, int b) { if (a > b) swap(a, b); if (a <= b) cout << ar[a]; for (int i = a + 1; i <= b; i++) cout << " " << ar[i]; cout << endl; } void P_BIN(int n) { if (n == 0) return; P_BIN(n / 2); printf("%d", n % 2); } int nxt[500007], prv[500007]; int ar[500007], aa[500007]; struct data { int id, mxval; data() {} } tree[4 * 500007]; void build(int idx, int s, int e) { if (s == e) { tree[idx].mxval = ar[s]; tree[idx].id = s; return; } int mid = (s + e) >> 1, l = (idx << 1), r = l | 1; build(l, s, mid); build(r, mid + 1, e); if (tree[l].mxval < tree[r].mxval) tree[idx] = tree[l]; else tree[idx] = tree[r]; } void update(int idx, int s, int e, int pos, int val) { if (s == e) { tree[idx].mxval = val; return; } int mid = (s + e) >> 1, l = (idx << 1), r = l | 1; if (pos <= mid) update(l, s, mid, pos, val); else update(r, mid + 1, e, pos, val); if (tree[l].mxval < tree[r].mxval) tree[idx] = tree[l]; else tree[idx] = tree[r]; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); ; int tc, cas = 1; int a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z; cin >> n; for (i = 1; i <= n; i++) cin >> ar[i]; for (i = 1; i <= n; i++) { nxt[i] = i + 1; prv[i] = i - 1; } build(1, 1, n); c = n - 2; long long int ans = 0; for (i = 1; i <= c; i++) { data tt = tree[1]; x = prv[tt.id]; y = nxt[tt.id]; if (min(ar[x], ar[y]) == 0) ans += ar[tt.id]; else ans += min(ar[x], ar[y]); nxt[x] = y; prv[y] = x; update(1, 1, n, tt.id, 1000000000); } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; const int MAXN = 1000 * 1000 + 10; int a[MAXN], b[MAXN], n[MAXN]; bool mark[MAXN]; set<pair<int, int> > st; int main() { int m; cin >> m; for (int i = 0; i < m; i++) { cin >> a[i]; b[i] = i - 1; n[i] = i + 1; st.insert(make_pair(a[i], i)); } long long ans = 0; while (!st.empty()) { int i = st.begin()->second; st.erase(st.begin()); if (i == 0 || i == m - 1) continue; if (a[i] <= a[b[i]] && a[i] <= a[n[i]]) { ans += min(a[b[i]], a[n[i]]); n[b[i]] = n[i]; b[n[i]] = b[i]; mark[i] = true; } } int mx[3] = {0, 0, 0}; for (int i = 0; i < m; i++) { if (!mark[i]) { mx[2] = a[i]; sort(mx, mx + 3, greater<int>()); ans += a[i]; mark[i] = true; } } ans -= (mx[0] + mx[1]); cout << ans << endl; }
#include <bits/stdc++.h> using namespace std; const double eps = 1e-8; const double pi = acos(-1.0); const int N = 500005; int s[N]; int main() { int n, top = 0; long long ans = 0; scanf("%d", &n); for (int i = 0; i < n; i++) { int x; scanf("%d", &x); while (top > 1 && s[top - 2] >= s[top - 1] && x >= s[top - 1]) { ans += min(x, s[top - 2]); top--; } s[top++] = x; } sort(s, s + top); for (int i = 0; i < top - 2; i++) ans += s[i]; cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int main() { int n; int a[500005]; cin >> n; int m = -1; long long ans = 0; for (int k = 0; k < n; ++k) { cin >> a[++m]; while (m >= 2 && a[m - 1] <= min(a[m - 2], a[m])) { ans += min(a[m - 2], a[m]); a[m - 1] = a[m]; --m; } } for (int k = 1; k < m; ++k) { ans += min(a[k - 1], a[k + 1]); } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int cmp(int x, int y) { if (x > y) return y; else return x; } int main(void) { int n, i = 0; long long int score = 0; cin >> n; int mas[500007]; for (int j = 0; j < n; j++) { cin >> mas[i++]; while ((i > 2) && (mas[i - 2] <= min(mas[i - 3], mas[i - 1]))) { score += min(mas[i - 1], mas[i - 3]); mas[i - 2] = mas[i - 1]; i--; } } sort(mas, mas + i); for (int j = 0; j < i - 2; j++) score += mas[j]; cout << score; return 0; }
#include <bits/stdc++.h> using namespace std; int a[500005]; bool cmp(int x, int y) { return (a[x] < a[y]); } int main() { int n; scanf("%d", &n); vector<int> v; set<int> s; for (int i = 0; i < n; i++) { scanf("%d", &a[i]); s.insert(i); v.push_back(i); } sort(v.begin(), v.end(), cmp); long long ans = 0; queue<int> q; for (int i : v) { auto it = s.find(i); if (it != s.begin() && next(it) != s.end()) ans += min(a[*prev(it)], a[*next(it)]); else { q.push(i); if (q.size() > 2) { ans += a[q.front()]; q.pop(); } } s.erase(it); } printf("%I64d", ans); }
#include <bits/stdc++.h> using std::min; const int N = 5e5 + 10; int n; long long tot, val[N], pre[N], nxt[N]; inline int calc(int p) { if (p == 1 or p == n) return 0; return min(val[pre[p]], val[nxt[p]]); } int main() { scanf("%d", &n); for (int i = 1; i <= n; ++i) scanf("%I64d", &val[i]), pre[i] = i - 1, nxt[i] = i + 1; for (int i = 2; i <= n - 1; i = nxt[i]) { while (val[pre[i]] >= val[i] and val[nxt[i]] >= val[i]) { tot += calc(i); nxt[pre[i]] = nxt[i]; pre[nxt[i]] = pre[i]; i = pre[i]; } } int p = 0, maxval = 0; for (int i = nxt[1]; i <= n; i = nxt[i]) if (calc(i) > maxval) p = i, maxval = calc(i); while (p > 1 and p < n) { tot += calc(p); nxt[pre[p]] = nxt[p]; pre[nxt[p]] = pre[p]; p = (calc(pre[p]) >= calc(nxt[p])) ? pre[p] : nxt[p]; } printf("%I64d\n", tot); return 0; }
#include <bits/stdc++.h> using namespace std; const long long maxN = 5e5 + 10; long long n, a[maxN], nxt[maxN], prv[maxN]; set<pair<long long, long long> > s; long long res = 0; int32_t main() { cin >> n; for (long long i = 0; i < n; i++) { cin >> a[i]; prv[i] = i - 1; nxt[i] = i + 1; s.insert(make_pair(a[i], i)); } long long l = 0, r = n - 1; long long res = 0; while (s.size() > 2) { long long x = s.begin()->first; long long pos = s.begin()->second; s.erase(s.begin()); if (pos == l) { res += x; l = nxt[l]; } else if (pos == r) { res += x; r = prv[r]; } else { res += min(a[prv[pos]], a[nxt[pos]]); nxt[prv[pos]] = nxt[pos]; prv[nxt[pos]] = prv[pos]; } } cout << res << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int N, A[555555]; int Next[555555], Prev[555555]; queue<int> q; long long ans; bool dip(int i) { return i != 0 && i != N - 1 && A[Prev[i]] > A[i] && A[Next[i]] >= A[i]; } int main(int argc, char *argv[]) { scanf("%d", &N); for (int i = 0; i < (N); i++) scanf("%d", A + i); if (N == 1) { printf("0\n"); return 0; } for (int i = 0; i < (N); i++) { Next[i] = i + 1; Prev[i] = i - 1; } for (int i = 0; i < (N); i++) if (dip(i)) q.push(i); while (!q.empty()) { int n = q.front(), l = Prev[n], r = Next[n]; q.pop(); ans += min(A[l], A[r]); Prev[r] = l; Next[l] = r; if (dip(l)) q.push(l); if (dip(r)) q.push(r); } vector<int> v; int p = 0; while (p != N) { v.push_back(p); p = Next[p]; } int l = 0, r = (int)v.size() - 1; while (l + 1 != r) { ans += min(A[v[l]], A[v[r]]); if (min(A[v[l]], A[v[r - 1]]) > min(A[v[l + 1]], A[v[r]])) r--; else l++; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int n, a[500001]; int main() { scanf("%d", &n); int i, top = -1; long long ans = 0; for (i = 1; i <= n; i++) { int x; scanf("%d", &x); while (top >= 1 && a[top] <= a[top - 1] && a[top] <= x) { ans += min(a[top - 1], x); top--; } a[++top] = x; } sort(a, a + top + 1); for (i = 0; i < top - 1; i++) ans += a[i]; printf("%lld\n", ans); return 0; }
#include <bits/stdc++.h> using namespace std; int n, nxt[500005], prv[500005], a[500005]; long long rez; pair<int, int> v[500005]; int main() { cin >> n; for (int i = 0; i < n; ++i) { cin >> a[i]; v[i] = make_pair(a[i], i); nxt[i] = i + 1; prv[i] = i - 1; } sort(v, v + n); int f = 0, l = n - 1; for (int i = 0; i < n - 2; ++i) { int ind = v[i].second; if (ind == f) { rez += v[i].first; f = nxt[f]; continue; } if (ind == l) { rez += v[i].first; l = prv[l]; continue; } if (ind == 0 || ind == n - 1) continue; rez += min(a[prv[ind]], a[nxt[ind]]); prv[nxt[ind]] = prv[ind]; nxt[prv[ind]] = nxt[ind]; } cout << rez; }
#include <bits/stdc++.h> using namespace std; int MAXN = 500005; vector<int> v(MAXN); vector<int> prv(MAXN); vector<int> nxt(MAXN); vector<int> add(500005); queue<int> q; void check(int idx) { if (add[idx]) return; if (v[prv[idx]] >= v[idx] and v[idx] <= v[nxt[idx]]) { add[idx] = 1; q.push(idx); } } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int n; cin >> n; nxt[0] = 1; prv[n + 1] = n; for (int i = 1; i <= n; i++) { cin >> v[i]; prv[i] = i - 1; nxt[i] = i + 1; } for (int i = 1; i <= n; i++) check(i); long long ans = 0; while (!q.empty()) { int idx = q.front(); q.pop(); nxt[prv[idx]] = nxt[idx]; prv[nxt[idx]] = prv[idx]; ans += min(v[prv[idx]], v[nxt[idx]]); check(prv[idx]); check(nxt[idx]); } int idx = nxt[0]; while (idx != n + 1) { ans += min(v[prv[idx]], v[nxt[idx]]); idx = nxt[idx]; } cout << ans << '\n'; return 0; }
#include <bits/stdc++.h> using namespace std; const int nmax = 5e5 + 42; int n, arr[nmax]; int l[nmax], r[nmax]; stack<pair<int, int> > help, emp; pair<int, int> work[nmax]; bool cmp(pair<int, int> a, pair<int, int> b) { if (a.first != b.first) return a.first < b.first; return a.second < b.second; } int main() { cin >> n; for (int i = 1; i <= n; i++) scanf("%i", &arr[i]); for (int i = 1; i <= n; i++) { while (help.size() && arr[i] >= help.top().first) help.pop(); if (help.size() == 0) l[i] = -1; else l[i] = help.top().second; help.push({arr[i], i}); } help = emp; for (int i = n; i >= 1; i--) { while (help.size() && arr[i] >= help.top().first) help.pop(); if (help.size() == 0) r[i] = n + 1; else r[i] = help.top().second; help.push({arr[i], i}); } for (int i = 1; i <= n; i++) work[i] = {arr[i], i}; sort(work + 1, work + n + 1, cmp); long long ans = 0; int prev = 0; for (int i = 1; i + 2 <= n; i++) { int j = i; while (work[i].first == work[j].first) j++; j--; ans = ans + 1LL * (work[i].first - prev) * (n - 1 - i); prev = work[i].first; for (int k = i; k <= j; k++) if (l[work[k].second] != -1 && r[work[k].second] != n + 1) { if (k == i || l[work[k].second] != l[work[k - 1].second]) { ans = ans + min(arr[l[work[k].second]], arr[r[work[k].second]]) - prev; } } i = j; } cout << ans << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int n; int in[10000009]; int lef[1000009], ri[1000009]; int fixx[1000009], val[1000009]; vector<pair<int, int> > data; int main() { scanf("%d", &n); if (n == 1) { scanf("%d", &n); cout << 0 << endl; return 0; } for (int i = 0; i < (int)n; i++) { scanf("%d", &in[i]); ; fixx[i] = 0; val[i] = 0; data.push_back(make_pair(in[i], i)); } for (int i = 0; i < (int)n; i++) { if (i == 0) { lef[i] = -1; ri[i] = i + 1; } else if (i == n - 1) { ri[i] = -1; lef[i] = i - 1; } else { lef[i] = i - 1; ri[i] = i + 1; } } sort(data.begin(), data.end()); long long sum = 0; for (int i = 0; i < (int)n; i++) { int x = data[i].first; int pos = data[i].second; if (pos == 0 || pos == n - 1) { fixx[pos] = 1; val[pos] = 0; continue; } if (fixx[ri[pos]] == 1 || fixx[lef[pos]] == 1) { fixx[pos] = 1; val[pos] = min(in[ri[pos]], in[lef[pos]]); continue; } sum += min(in[ri[pos]], in[lef[pos]]); ri[lef[pos]] = ri[pos]; lef[ri[pos]] = lef[pos]; } for (int i = 0; i < (int)n; i++) { if (fixx[i] == 1) { sum += val[i]; } } cout << sum << endl; }
#include <bits/stdc++.h> using namespace std; const int MAX = 1e6 + 10; template <typename T> inline void read(T &a) { T w = 1; a = 0; char ch = getchar(); for (; !isdigit(ch); ch = getchar()) if (ch == '-') w = -1; for (; isdigit(ch); ch = getchar()) a = (a << 3) + (a << 1) + (ch ^ 48); a *= w; } long long a[MAX], b[MAX]; stack<long long> pos; signed main() { long long n; read(n); long long ans = 0, tot = 0; for (register long long i = 1; i <= n; ++i) { read(a[i]); while (pos.size() >= 2) { long long x = pos.top(); pos.pop(); long long y = pos.top(); if (y >= x && x <= a[i]) { ans += min(y, a[i]); } else { pos.push(x); break; } } pos.push(a[i]); } while (!pos.empty()) { b[++tot] = pos.top(); pos.pop(); } sort(b + 1, b + tot + 1); for (register long long i = 1; i <= tot - 2; ++i) { ans += b[i]; } cout << ans; }
#include <bits/stdc++.h> using namespace std; const int maxn = 100005; const int maxk = 105; vector<pair<int, long double> > f, tmp; long double g[maxn], t[maxn]; long double ans; int n, k; int main() { scanf("%d%d", &n, &k); f.push_back(make_pair(1, 1.0)); for (int i = 0; i < n; ++i) { tmp.clear(); for (int k = 0; k < (int)f.size(); ++k) { int j = f[k].first; long double p = f[k].second; if (p < 1e-15) continue; g[i + 1] += p * (j * 1.0 / (j + 1)) * ((j + 1) / 2.0); tmp.push_back(make_pair(j, p * (j * 1.0 / (j + 1)))); g[i + 1] += p * (1.0 / (j + 1)) * j; tmp.push_back(make_pair(j + 1, p * (1.0 / (j + 1)))); } pair<int, long double> last = tmp[0]; f.clear(); for (int k = 1; k < (int)tmp.size(); ++k) if (tmp[k].first == last.first) last.second += tmp[k].second; else { f.push_back(last); last = tmp[k]; } f.push_back(last); } for (int i = 1; i <= n; ++i) g[i] += g[i - 1]; if (k > 1) { t[0] = log(1); for (int i = 1; i <= n; ++i) t[0] = t[0] + log(k - 1) - log(k); for (int i = 1; i <= n; ++i) t[i] = t[i - 1] + log(n - i + 1) - log(i) - log(k - 1); for (int i = 1; i <= n; ++i) t[i] = exp(t[i]); } else { t[n] = 1; } for (int i = 0; i <= n; ++i) ans += g[i] * t[i]; ans *= k; printf("%.100lf\n", (double)ans); return 0; }
#include <bits/stdc++.h> using namespace std; void enable_comma() {} string tostring(char c) { string s = ""; s += c; return s; } string tostring(string s) { return "\"" + s + "\""; } string tostring(const char *c) { return tostring((string)c); } string tostring(long long x) { if (x < 0) return "-" + tostring(-x); if (x > 9) return tostring(x / 10) + tostring(char('0' + x % 10)); else return tostring(char('0' + x)); } string tostring(int x) { return tostring((long long)x); } string tostring(unsigned long long x) { if (x > 9) return tostring((long long)(x / 10)) + tostring(char('0' + x % 10)); else return tostring(char('0' + x)); } string tostring(unsigned x) { return tostring((long long)x); } string tostring(double x) { static char res[114]; sprintf(res, "%lf", x); string s = tostring(res); return s.substr(1, (int)s.size() - 2); } string tostring(long double x) { return tostring((double)x); } template <class A, class B> string tostring(pair<A, B> p) { return "(" + tostring(p.first) + "," + tostring(p.second) + ")"; } template <class T> string tostring(T v) { string res = ""; for (auto p : v) res += (res.size() ? "," : "{") + tostring(p); return res.size() ? res + "}" : "{}"; } template <class A> string tostring(A *a, int L, int R) { return tostring(vector<A>(a + L, a + R + 1)); }; template <class A> string tostring(A a, int L, int R) { return tostring(a.data(), L, R); } string tostrings() { return ""; } template <typename Head, typename... Tail> string tostrings(Head H, Tail... T) { return tostring(H) + " " + tostrings(T...); } long long read() { long long x = 0, f = 0; char ch = getchar(); while (!isdigit(ch)) f = ch == '-', ch = getchar(); while (isdigit(ch)) x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar(); return f ? -x : x; } template <class T> void ckmax(T &x, const T y) { if (x < y) x = y; } template <class T> void ckmin(T &x, const T y) { if (x > y) x = y; } const int N = 100005, M = 1005; int n, m = M - 5, k; long double p[M], pp[M]; void solve() { n = read(), k = read(); p[1] = 1; long double ans = 0; for (int i = (1); i <= (n); i++) { memset(pp, 0, sizeof(pp)); for (int j = (1); j <= (m); j++) { ans += p[j] * ((1 + j + 1) * (j + 1) / 2 - 1) / (j + 1) / k; pp[j] += p[j] * j / (j + 1); pp[j + 1] += p[j] / (j + 1); } for (int j = (1); j <= (m); j++) { p[j] = (p[j] * (k - 1) + pp[j]) / k; } } ans *= k; printf("%.10lf\n", (double)ans); } int main() { int T = 1; while (T--) solve(); return 0; }
#include <bits/stdc++.h> using namespace std; using ld = long double; int const MAGIC = 700; ld f[2][MAGIC]; ld *cur = f[0], *nxt = f[1]; int main() { int N, K; scanf("%d%d", &N, &K); for (int i = 1; i <= N; ++i) { for (int j = 1; j < MAGIC; ++j) { nxt[j] = ((j * cur[j] + cur[j + 1] + j) / (j + 1) + j / 2.) / K + (1 - 1. / K) * cur[j]; } swap(cur, nxt); } printf("%.20lf\n", (double)cur[1] * K); return 0; }
#include <bits/stdc++.h> using namespace std; template <typename T, typename U> inline void amin(T &x, U y) { if (y < x) x = y; } template <typename T, typename U> inline void amax(T &x, U y) { if (x < y) x = y; } int main() { int n, k; scanf("%d%d", &n, &k); const int MaxLv = 900; vector<vector<long double> > dp(2, vector<long double>(MaxLv + 1, 0)); for (int(j) = (int)(1); (j) <= (int)(MaxLv); ++(j)) dp[n & 1][j] = 0; for (int i = n - 1; i >= 0; --i) for (int(j) = (int)(1); (j) <= (int)(MaxLv); ++(j)) { long double r = 0; long double selectedProb = 1.L / k; r += (1 - selectedProb) * (dp[i + 1 & 1][j] + 0); long double levelupProb = 1.L / (j + 1); if (j + 1 <= MaxLv) r += (dp[i + 1 & 1][j + 1] + j * k) / (k * (j + 1)); r += (1 - levelupProb) * (dp[i + 1 & 1][j] + (j + 1) * k / 2.L) / k; dp[i & 1][j] = r; } long double ans = dp[0 & 1][1]; printf("%.15f\n", (double)ans); return 0; }
#include <bits/stdc++.h> using namespace std; int N, K; double dp[2][605]; int main() { scanf("%d %d", &N, &K); for (int i = N - 1; i >= 0; i--) { int cur = i & 1; int nex = cur ^ 1; for (int j = 1; j <= 600; j++) { double a = (j + dp[nex][j + 1]) / (j + 1.0); double b = (j * (1 + j) / 2.0 + j * dp[nex][j]) / (j + 1.0); dp[cur][j] = (a + b) / K + dp[nex][j] * (1 - 1.0 / K); } } printf("%.10lf\n", K * dp[0][1]); }
#include <bits/stdc++.h> using namespace std; double dp[2][600 + 10]; int main(void) { int N, K, i, j; double ans = 0.0; cin >> N >> K; dp[0][1] = 1.0; for ((i) = 0; (i) < (int)(N); (i)++) { int cur = i % 2, next = (i + 1) % 2; for ((j) = 0; (j) < (int)(600); (j)++) ans += dp[cur][j] * (j / 2.0 + j / (j + 1.0)); for ((j) = 0; (j) < (int)(600); (j)++) dp[next][j] = dp[cur][j] * (1.0 - 1.0 / (j + 1.0) / K); for ((j) = 0; (j) < (int)(600); (j)++) dp[next][j + 1] += dp[cur][j] / (j + 1.0) / K; for ((j) = 0; (j) < (int)(600); (j)++) if (dp[next][j] < 1.0E-100) dp[next][j] = 0.0; } printf("%.12f\n", ans); return 0; }
#include <bits/stdc++.h> const int MAXN = 525; int n, k; double dp[2][MAXN + 5]; int main() { scanf("%d %d", &n, &k); for (int i = 1; i <= n; i++) for (int j = 1; j <= MAXN; j++) dp[i & 1][j] = (dp[(i - 1) & 1][j] * ((k - 1) * 1.0 / k) + (dp[(i - 1) & 1][j + 1] + j) * (1.0 / (k * (j + 1))) + (dp[(i - 1) & 1][j] + (1 + j) / 2.0) * (j * 1.0 / (k * (j + 1)))); printf("%.10f\n", dp[n & 1][1] * k); return 0; }
#include <bits/stdc++.h> using namespace std; const int N = 100100; double ans, f[2][N]; int now, n, k; int main() { scanf("%d%d", &n, &k); now = 0; for (int i = n - 1; i >= 0; i--) { now ^= 1; for (int j = 1; j <= 600; j++) f[now][j] = f[now ^ 1][j] * (j * 1.0 / (j + 1.0) / k + (k - 1) * 1.0 / k) + (j * 1.0 / 2 + j * 1.0 / (j + 1)) / k + 1.0 / (j + 1) * f[now ^ 1][j + 1] / k; } printf("%.12lf\n", k * f[now][1]); }
#include <bits/stdc++.h> using namespace std; int n, k, m = 700; double f[100010]; void Work() { for (int i = 1; i <= n; i++) for (int j = 1; j <= m; j++) f[j] = ((double)j / (j + 1) * f[j] + (double)j / 2 + (f[j + 1] + j) / (j + 1) + f[j] * (k - 1)) / k; printf("%.10lf\n", f[1] * k); } void Init() { scanf("%d%d", &n, &k); } int main() { Init(); Work(); return 0; }
#include <bits/stdc++.h> const int N = 525; int n, k; double f[2][N + 5]; int main() { scanf("%d%d", &n, &k); for (int i = 1; i <= n; i++) for (int j = 1; j <= N; j++) f[i & 1][j] = (f[i & 1 ^ 1][j] * (k - 1. / (j + 1)) + f[i & 1 ^ 1][j + 1] / (j + 1) + j * (j + 3.) / 2 / (j + 1)) / k; printf("%.10f\n", f[n & 1][1] * k); return 0; }
#include <bits/stdc++.h> using namespace std; int main(int argc, char* argv[]) { long long int n, k; cin >> n >> k; double log_acc = 1.0; double log_phi = log(1.0 / (k - 1.0)); double res = 0.0; double es[100001]; for (int i = 0; i <= n; ++i) es[i] = 0; for (long long int m = 0; m <= n; ++m) { if (0 == m) log_acc = n * log(1.0 - 1.0 / k); double ee = es[1]; res += exp(log_acc) * ee; log_acc += log_phi + log(n - m) - log(1.0 + m); if (k == 1 && n == m) res = ee; for (int l = 0; l <= 700; ++l) { double p = 1.0 / (l + 1.0); es[l] = (1.0 - p) * es[l] + l / 2.0 + p * (l + es[l + 1]); } } printf("%.14f\n", res * k); return 0; }
#include <bits/stdc++.h> using namespace std; int read() { register int x = 0, f = 1; char ch = getchar(); while (ch < '0' || ch > '9') { if (ch == '-') f = -1; ch = getchar(); } while (ch >= '0' && ch <= '9') { x = 10 * x + ch - '0'; ch = getchar(); } return x * f; } const int Size = 1005; const int INF = 0x3f3f3f3f; double dp[2][Size]; int main() { int n = read(); int k = read(); int maxl = min(n, 700); double p = (double)(k - 1) / k; for (register int i = 1; i <= n; i++) { register int now = i & 1, pre = now ^ 1; for (register int j = 1; j <= maxl; j++) { dp[now][j] = p * dp[pre][j] + (1 - p) * ((dp[pre][j + 1] + j) / (j + 1) + (dp[pre][j] + (j + 1) / 2.0) * j / (j + 1)); } } printf("%.10lf", dp[n & 1][1] * k); return 0; }
#include <bits/stdc++.h> using namespace std; inline long long int mod(long long int a, long long int b, long long int x = 1000000007) { long long int res = 1; a = a % x; while (b > 0) { if (b & 1) { res = (res * a) % x; } b = b >> 1; a = (a * a) % x; } return res; } inline long long int gcd(long long int a, long long int b) { long long int r; while (b) { r = a % b; a = b; b = r; } return a; } inline long long int lcm(long long int a, long long int b) { return a / gcd(a, b) * b; } inline long long int left(long long int i) { return (i << 1); } inline long long int right(long long int i) { return ((i << 1) + 1); } const int maxn = 1e5 + 5; const int maxx = 1e6 + 5; const int logn = 316; double ans[100005]; int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); long long int n, k; cin >> n >> k; long long int m = min(650ll, n); for (long long int i = 1; i <= n; i++) { for (long long int j = 1; j <= m; j++) { ans[j] = 1.0 / k / (j + 1) * (j * ans[j] + ans[j + 1] + j * (j + 3.0) / 2.0) + 1.0 * (k - 1) / k * ans[j]; } } cout << fixed << setprecision(12); cout << ans[1] * k << "\n"; return 0; }
#include <bits/stdc++.h> using namespace std; double dp[2][800]; int n, k; int main() { scanf("%d%d", &n, &k); dp[0][1] = 0; for (int i = 1; i <= n; ++i) { int cur = i & 1 ^ 1; int nxt = cur ^ 1; for (int t = 1; t + 1 < 800; ++t) { dp[nxt][t] = dp[cur][t + 1] + t * dp[cur][t] + (t * t + 0.0 + 3 * t) / 2; dp[nxt][t] /= k * (t + 1); dp[nxt][t] += (k - 1.0) / k * dp[cur][t]; } } printf("%.12lf\n", dp[n & 1][1] * k); return 0; }
#include <bits/stdc++.h> using namespace std; long double f[2333], p[2333], ans, ess; int n, k; int main() { scanf("%d%d", &n, &k); for (int i = 2333; i >= 0; i--) f[i] = 0, p[i] = 1.0 / i; f[1] = 1.0; for (int i = 1; i <= n; i++) { for (int j = 2000; j >= 0; j--) { if (fabs(f[j]) <= 1e-23) { f[j] = 0; continue; } ans += f[j] * j * (0.5 + p[j + 1]); ess = f[j] * p[j + 1] * p[k]; f[j + 1] += ess; f[j] -= ess; } } printf("%.12lf\n", (double)ans); return 0; }
#include <bits/stdc++.h> using namespace std; const int MAXT = 610; double f[2][MAXT]; inline int Min(int a, int b) { return a < b ? a : b; } int main() { int N; double K; scanf("%d %lf", &N, &K); double p1 = 1.0 / K, p2; for (int i = N - 1, lim, c = i & 1; i >= 0; --i, c ^= 1) { lim = Min(600, i + 1); for (int t = 1; t <= lim; ++t) { p2 = 1.0 / (double)(t + 1); f[c][t] = p1 * (p2 * (f[c ^ 1][t + 1] + f[c ^ 1][t] * t + t * (t + 1) / 2 + t)) + (1.0 - p1) * (f[c ^ 1][t]); } } printf("%.10lf", f[0][1] * K); return 0; }
#include <bits/stdc++.h> using namespace std; #pragma comment(linker, "/STACK:128000000") const int maxl = 750; int n, k; double f[maxl]; double prec[maxl]; double nprec[maxl]; double me[maxl]; int main() { cin >> n >> k; double nk = 1.0 / (double)k; for (int i = 1; i < maxl; ++i) { me[i] = (double)(i + 1) / 2.0; prec[i] = (1.0 / (double)(i + 1)); nprec[i] = (1.0 - prec[i]); prec[i] *= nk; nprec[i] *= nk; } double res = 0.0; memset(f, 0, sizeof f); f[1] = 1.0; for (int i = 0; i < n; ++i) { double cf, dif; for (int j = min(maxl - 2, i + 1); j; --j) { cf = f[j]; dif = prec[j] * cf; f[j + 1] += dif; res += nprec[j] * cf * me[j]; res += dif * (double)j; f[j] = cf - dif; } } cout.precision(15); cout << fixed << res * (double)k << endl; return 0; }
#include <bits/stdc++.h> using namespace std; int main(void) { srand(time(0)); cout << fixed << setprecision(9); cerr << fixed << setprecision(9); static long double dp[1 << 20]; static long double inv[1 << 20]; int n, k; cin >> n >> k; for (int i = 1; i <= 1e6; ++i) inv[i] = (long double)(1.0) / i; long double ans = 0; dp[1] = 1; for (int rep = 1; rep <= n; ++rep) { for (int j = min(rep, 1000); j; --j) { const long double prob = inv[k] * dp[j] * inv[j + 1]; ans += dp[j] * j * (0.5 + inv[j + 1]); dp[j] -= prob; dp[j + 1] += prob; } } cout << ans << '\n'; cerr << "Time elapsed :" << clock() * 1000.0 / CLOCKS_PER_SEC << " ms" << '\n'; return 0; }
#include <bits/stdc++.h> using namespace std; const long double eps = 1e-8; const long double PI = acos(-1.); const long long MOD = 1000000007; long double dp[2][1555]; long double inv[1555]; int main() { int i, j, k, T; for (i = 1; i <= 1501; i++) inv[i] = ((long double)1) / i; int n = 100000, m = 1; while (~scanf("%d%d", &n, &m)) { memset(dp, 0, sizeof dp); long double ans = 0; dp[0][1] = 1; for (i = 0; i < n; i++) { int x = i % 2, y = (i + 1) % 2; int MX = 600; for (j = 1; j <= MX; j++) ans += dp[x][j] * j * (inv[j + 1] + inv[2]); for (j = 1; j <= MX; j++) dp[y][j] = dp[x][j] * (1. - inv[j + 1] * inv[m]); for (j = 1; j <= MX; j++) dp[y][j + 1] += dp[x][j] * inv[j + 1] * inv[m]; } printf("%.16f\n", (double)ans); } return 0; }
#include <bits/stdc++.h> using namespace std; const int maxn = 1e5 + 500; const int maxk = 700; long double dp[maxk]; int main() { int n, k; cin >> n >> k; long double ans = 0; dp[1] = 1; for (int i = 0; i < n; i++) { long double dj; long double dk = k; for (int j = maxk - 1; j >= 1; j--) { dj = j; ans += dp[j] * dj * (dj + 3) / (2 * (dj + 1)); dp[j] = (dp[j] * ((dk - 1) + dj / (dj + 1)) + dp[j - 1] / dj) / dk; } } cout << fixed << setprecision(12) << ans; }
#include <bits/stdc++.h> using namespace std; int n, k; double f[2][810]; int main() { scanf("%d%d", &n, &k); for (int i = 1; i * i <= n; ++i) f[0][i] = 0; int st = min(max(800.0, sqrt(n)), 1.0 * n); int c = 0; for (int i = 1; i <= n; ++i) { c ^= 1; for (int j = 1; j <= st; ++j) { f[c][j] = 1.0 * (k - 1) / k * f[c ^ 1][j] + 1.0 * j / k / (j + 1) * f[c ^ 1][j] + 1.0 / k / (j + 1) * (f[c ^ 1][j + 1] + (1.0 + j) * j / 2.0 + j); if (f[c][j] <= 1e-100) f[c][j] = 0; } } printf("%.10lf", f[c][1] * k); return 0; }
#include <bits/stdc++.h> int n, k; long double _ldp[708], _dp[708], *ldp = _ldp, *dp = _dp; int main() { scanf("%d%d", &n, &k); memset(dp, 0, sizeof(_dp)); memset(ldp, 0, sizeof(_dp)); for (int T = (1); T <= (n); ++T) { for (int L = (1); L <= (700); ++L) dp[L] = ((L * (ldp[L] + (L + 1) / 2.0) + ldp[L + 1] + L) / (L + 1) + ldp[L] * (k - 1)) / k; std::swap(dp, ldp); } printf("%.20lf\n", (double)(ldp[1] * k)); return 0; }
#include <bits/stdc++.h> using namespace std; double DP[705], Pre[705]; int n, k; double ans = 0; int main() { cin >> n >> k; int sq = 700; for (int i = 1; i <= n; i++) { for (int j = 1; j <= sq; j++) DP[j] = 1.0 / k / (j + 1) * (Pre[j] * j + Pre[j + 1] + j * (j + 3) / 2) + 1.0 * (k - 1) / k * Pre[j]; for (int j = 1; j <= sq; j++) Pre[j] = DP[j]; } printf("%0.12f", DP[1] * k); }
#include <bits/stdc++.h> int n, k; long double _ldp[708], _dp[708], *ldp = _ldp, *dp = _dp, E[100086]; int main() { scanf("%d%d", &n, &k); E[0] = 0; memset(dp, 0, sizeof(_dp)); memset(ldp, 0, sizeof(_dp)); for (int T = (1); T <= (n); ++T) { for (int L = (1); L <= (700); ++L) dp[L] = ((L * (ldp[L] + (L + 1) / 2.0) + ldp[L + 1] + L) / (L + 1) + ldp[L] * (k - 1)) / k; E[T] = dp[1]; std::swap(dp, ldp); } printf("%.20lf\n", (double)(E[n] * k)); return 0; }
#include <bits/stdc++.h> using namespace std; double D[703][2]; int n, k; int main() { cin >> n >> k; for (int i = 1; i <= n; ++i) { int p = (i % 2); int r = !p; for (int j = 1; j <= 700; ++j) D[j][p] = 1.0 / (k * (j + 1)) * (j * D[j][r] + D[j + 1][r] + j * (j + 3) / 2) + D[j][r] * (k - 1) / k; } cout << fixed << setprecision(11) << D[1][n % 2] * k; return 0; }
#include <bits/stdc++.h> using namespace std; template <typename T> T abs(T x) { return x > 0 ? x : -x; } const int maxk = 800; long double a[maxk]; long double b[maxk]; int main(int argc, char *argv[]) { int n, k; cin >> n >> k; a[1] = k; long double ans = 0; for (int i = 0; i < n; i++) { for (int j = 1; j < maxk; j++) { b[j] = a[j] * (1.0 - 1.0 / (k * (j + 1))) + a[j - 1] / (k * j); } long double sum = 0; for (int j = 1; j < maxk; j++) { ans += (a[j] / k) * ((long double)j * (j + 1) / 2 / (j + 1) + (long double)j / (j + 1)); a[j] = b[j]; if (a[j] < 1e-50) a[j] = 0; } } cerr << a[50] << endl; cout.precision(11); cout << fixed << ans; return 0; }
#include <bits/stdc++.h> using namespace std; const int maxn = 100005; const int maxj = 1000; int n, k; double dp[2][maxj]; int main() { fill(dp[0], dp[0] + maxj, 0.0); cin >> n >> k; for (int i = 1; i <= n; i++) { for (int j = 1; j < maxj - 1; j++) { double kk = (double)k; double jj = (double)j; dp[1][j] = 1.0 / (kk * (jj + 1.0)) * (jj * (jj + 3.0) / 2.0 + jj * dp[0][j] + dp[0][j + 1]) + (1.0 - 1.0 / kk) * dp[0][j]; } for (int j = 1; j < maxj - 1; j++) { dp[0][j] = dp[1][j]; } } cout << fixed << setprecision(10) << k * dp[1][1] << '\n'; return 0; }
#include <bits/stdc++.h> inline int rd() { char c = getchar(); while (!isdigit(c)) c = getchar(); int x = c - '0'; while (isdigit(c = getchar())) x = x * 10 + c - '0'; return x; } long double f[2][1001]; int n, k; void input() { n = rd(), k = rd(); } void solve() { int bound = std::min(n, 800); int cur = 1, pre = 0; for (int i = 1, _ = n; i <= _; i++) { cur ^= 1, pre ^= 1; for (int j = 1, _ = bound; j <= _; j++) f[cur][j] = (k - 1) * f[pre][j] / k + (j * f[pre][j] + f[pre][j + 1] + j * (j + 3) / 2) / (k * (j + 1)); } printf("%.12lf\n", (double)f[cur][1] * k); } int main() { input(); solve(); return 0; }
#include <bits/stdc++.h> using namespace std; const int NMAX = 1000000 + 5; int N, K; double dp[2][1005]; void compute_dp() { bool h = true; for (int n = 1; n <= N; ++n, h ^= 1) { memset(dp[h], 0, sizeof dp[h]); for (int t = min(1000, N - n + 1); t; --t) dp[h][t] = (dp[h ^ 1][t + 1] + t * dp[h ^ 1][t] + t * (t + 3.0) / 2.0) / (K * (t + 1.0)) + ((K - 1.0) * dp[h ^ 1][t]) / K; } } int main() { cin >> N >> K; compute_dp(); cout << fixed << setprecision(10) << K * dp[N & 1][1] << '\n'; return 0; }
#include <bits/stdc++.h> int n, k; double dp[1024], ndp[1024]; int main() { scanf("%d%d", &n, &k); for (int i = 0; i < n; ++i) { for (int t = 1; t < 1000; ++t) ndp[t] = dp[t] * (k - 1) / k + (t * dp[t] + dp[t + 1] + t * (t + 3) / 2) / k / (t + 1); for (int t = 1; t < 1000; ++t) dp[t] = ndp[t]; } printf("%.15f\n", k * dp[1]); return 0; }
#include <bits/stdc++.h> using namespace std; long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); } const int MAXN = 100000; const int MAXZ = 1000; int nwin, ntype; double E[2][MAXN + 1]; void run() { scanf("%d%d", &nwin, &ntype); int at = 0; E[at][0] = 0; for (int i = (1); i <= (nwin); ++i) E[at][i] = 1.0 * (MAXZ * (MAXZ + 1) / 2 + MAXZ) / ntype / (MAXZ + 1) + E[at][i - 1]; for (int z = MAXZ - 1; z >= 1; --z) { at = 1 - at; E[at][0] = 0; for (int i = (1); i <= (nwin); ++i) E[at][i] = 1.0 * (z * (z + 1) / 2 + z + E[1 - at][i - 1] - E[at][i - 1]) / ntype / (z + 1) + E[at][i - 1]; } printf("%.9lf\n", ntype * E[at][nwin]); } int main() { run(); return 0; }
#include <bits/stdc++.h> using namespace std; double f[100005]; int main() { int n, k, ub; scanf("%d%d", &n, &k); ub = min(n, 80000000 / n); for (int i = 1; i <= n; i++) for (int j = 1; j <= ub; j++) f[j] = (k - 1) * 1.0 / k * f[j] + 1.0 / k / (j + 1) * (j * f[j] + j * 0.5 * (j + 1) + f[j + 1] + j); printf("%.12lf\n", f[1] * k); }
#include <bits/stdc++.h> using namespace std; double dp[2][605]; int Max = 600; int main() { int n, k; while (cin >> n >> k) { memset(dp, sizeof(dp), 0); dp[0][1] = 1; int cur = 0; int next = 1; double ans = 0; for (int i = 1; i <= n; ++i) { for (int j = 1; j < Max; ++j) ans += dp[cur][j] * (j / 2.0 + j / (j + 1.0)); for (int j = 1; j < Max; ++j) dp[next][j] = dp[cur][j] * (1 - (1.0 / (j + 1) / k)); for (int j = 2; j < Max; ++j) dp[next][j] += dp[cur][j - 1] / j / k; for (int j = 0; j < Max; ++j) if (dp[next][j] < 1e-100) dp[next][j] = 0; cur = next; next = next ^ 1; } printf("%.9lf\n", ans); } return 0; }
#include <bits/stdc++.h> using namespace std; const int MAXN = 1e5 + 5, MAXT = 710; int N, K; double d[2][MAXT]; int main() { scanf("%d%d", &N, &K); for (int i = 0; i < MAXT; i++) { d[0][i] = 0; } int c = 1; for (int i = 0; i < N; i++) { for (int j = 0; j < MAXT - 1; j++) { d[c][j] = 1.0 / (K * (j + 1)) * (j * d[c ^ 1][j] + d[c ^ 1][j + 1] + j * (j + 3) / 2.0) + (K - 1.0) / K * d[c ^ 1][j]; } c ^= 1; } printf("%.10lf\n", d[c ^ 1][1] * K); return 0; }
#include <bits/stdc++.h> using namespace std; int n, k; double f[2][1010]; int main() { scanf("%d%d", &n, &k); int now = 1; int t = min(n, 1000); for (int i = 1; i <= n; i++, now ^= 1) { for (int j = t; j; j--) { f[now][j] = ((f[now ^ 1][j + 1] + j) / (j + 1.0) + j * (f[now ^ 1][j] + (j + 1.0) / 2.0) / (j + 1.0)) / (k * 1.0) + (k - 1) * f[now ^ 1][j] / (k * 1.0); } } printf("%.10lf", f[now ^ 1][1] * k); return 0; }
#include <bits/stdc++.h> using namespace std; int n, m, x, sum[1010]; long double f[1010][2], g[1010][2], ans, p[1010], P; int main() { scanf("%d%d", &n, &m); g[1][0] = 1.; double P = 1. / (long double)m; for (int i = 1; i <= 810; i++) p[i] = 1. / (long double)i, sum[i] = (1 + i) * i / 2; for (int i = 1; i <= n; i++) { x ^= 1; for (int j = 1; j <= min(800, i + 1); j++) { f[j][x] = f[j][x ^ 1] * (m - 1) * P; g[j][x] = g[j][x ^ 1] * (m - 1) * P; g[j][x] += (g[j - 1][x ^ 1] * p[j] + g[j][x ^ 1] * j * p[j + 1]) * P; f[j][x] += ((f[j - 1][x ^ 1] + (j - 1) * g[j - 1][x ^ 1]) * p[j] + (j * f[j][x ^ 1] + sum[j] * g[j][x ^ 1]) * p[j + 1]) * P; } } for (int i = 1; i <= min(800, n + 1); i++) ans += f[i][x] * m; printf("%.12lf\n", (double)ans); }
#include <bits/stdc++.h> using namespace std; int read() { register int x = 0, f = 1; char ch = getchar(); while (ch < '0' || ch > '9') { if (ch == '-') f = -1; ch = getchar(); } while (ch >= '0' && ch <= '9') { x = 10 * x + ch - '0'; ch = getchar(); } return x * f; } const int Size = 1005; const int INF = 0x3f3f3f3f; double dp[2][Size]; int main() { int n = read(); int k = read(); int maxl = min(n, 700); double p = (double)(k - 1) / k; for (register int i = 1; i <= n; i++) { register int now = i & 1, pre = now ^ 1; for (register int j = 1; j <= maxl; j++) { dp[now][j] = p * dp[pre][j] + (1 - p) * ((dp[pre][j + 1] + j) / (j + 1) + (dp[pre][j] + (j + 1) / 2.0) * j / (j + 1)); } } printf("%.10lf", dp[n & 1][1] * k - (9e-10)); return 0; }
#include <bits/stdc++.h> using namespace std; int n, K, A; double f[2][710]; void read(int &x) { char ch = getchar(); int mark = 1; for (; ch != '-' && (ch < '0' || ch > '9'); ch = getchar()) ; if (ch == '-') mark = -1, ch = getchar(); for (x = 0; ch >= '0' && ch <= '9'; ch = getchar()) x = x * 10 + ch - 48; x *= mark; } int main() { read(n); read(K); A = 0; for (int i = 1; i <= n; i++) { A ^= 1; for (int j = 1; j <= min(n, 600); j++) f[A][j] = f[A ^ 1][j] * j / K / (j + 1) + f[A ^ 1][j] * (K - 1) / K + f[A ^ 1][j + 1] / K / (j + 1) + (double)j * (j + 3) / 2 / (j + 1); } printf("%.9lf\n", f[A][1]); return 0; }
#include <bits/stdc++.h> using namespace std; const double eps = 1e-8; int n, k; double E[2][600]; int main() { scanf("%d%d", &n, &k); for (int i = n - 1; i >= 0; i--) for (int j = 1; j < 600; j++) E[i % 2][j] = E[(i + 1) % 2][j] * (j * 1.0 / (j + 1) / k + (k - 1) * 1.0 / k) + (j * 1.0 / 2 + j * 1.0 / (j + 1)) / k + 1.0 / (j + 1) * E[(i + 1) % 2][j + 1] / k; printf("%.9lf\n", k * E[0][1]); return 0; }
#include <bits/stdc++.h> using namespace std; int n; double k; double f[2][1005]; int main() { cin >> n >> k; for (int i = 1, sta = 1; i <= n; ++i, sta ^= 1) for (int j = 1; j <= 1000; ++j) { f[sta][j] = (1 / k) * (((f[sta ^ 1][j] + (long double)(j + 1) / 2) * ((long double)j / (j + 1))) + (f[sta ^ 1][j + 1] + j) * ((long double)1 / (j + 1))) + ((k - 1) / k) * f[sta ^ 1][j]; } printf("%.10lf\n", f[n & 1][1] * k); return 0; }
#include <bits/stdc++.h> using namespace std; const double eps(1e-10); double E[2][600]; double res[600]; int main() { memset(E, 0, sizeof(E)); int n, k; scanf("%d %d", &n, &k); int now = 1; for (int j = 1; j < 600; j++) res[j] = (j * 1. / 2 + j * 1. / (j + 1)) / k; for (int i = n - 1; i >= 0; i--) { now ^= 1; for (int j = 1; j < 600; j++) E[now][j] = E[now ^ 1][j] * (j * 1. / (j + 1) / k + (k - 1) * 1. / k) + res[j] + 1. / (j + 1) * E[now ^ 1][j + 1] / k; } printf("%.9f\n", k * E[now][1]); return 0; }
#include <bits/stdc++.h> using namespace std; int n; double k; double dp[2][700 + 5]; int main() { scanf("%d %lf", &n, &k); int now = 0; for (int i = 1; i <= n; i++) { for (int j = 1; j <= 700; j++) { dp[now][j] = dp[now ^ 1][j] * (k - 1.0) / double(k) + ((dp[now ^ 1][j + 1] + j) / (j + 1.0) + (dp[now ^ 1][j] + (j + 1) / 2.0) * j / (j + 1.0)) / double(k); } now ^= 1; } printf("%.10lf\n", k * dp[now ^ 1][1]); }
#include <bits/stdc++.h> using namespace std; long n, k; double prob[10][1000 + 100]; double ans; double ev[10][1000 + 100]; double pup, prem; double rev[100000]; int main() { ios_base::sync_with_stdio(0); cin >> n >> k; double gz = 1.0 / k; for (int i = 1; i <= 1000 + 1000; i++) rev[i] = 1.0 / i; prob[0][1] = 1; ev[0][1] = 0; for (int i = 0; i < n; i++) { for (int j = 1; j <= 1000; j++) prob[1 - i % 2][j] = ev[1 - i % 2][j] = 0; long ths, nxt; ths = i % 2; nxt = 1 - ths; for (int j = 1; j <= 1000; j++) { if (prob[ths][j] < 1e-50) continue; ev[ths][j] /= prob[ths][j]; pup = gz * rev[j + 1]; prob[nxt][j + 1] += prob[ths][j] * pup; ev[nxt][j + 1] += (ev[ths][j] + j) * prob[ths][j] * pup; prem = gz * (1.0 - rev[j + 1]); prob[nxt][j] += prob[ths][j] * prem; ev[nxt][j] += (ev[ths][j] + (j + 1) * 0.5) * prob[ths][j] * prem; prob[nxt][j] += prob[ths][j] * (1.0 - gz); ev[nxt][j] += ev[ths][j] * (1.0 - gz) * prob[ths][j]; } } for (int i = 1; i <= 1000; i++) ans += ev[n % 2][i] * k; cout.precision(12); cout << fixed << ans << endl; cin.get(); cin.get(); return 0; }
#include <bits/stdc++.h> using namespace std; double a[700 + 5], b[700 + 5]; int n, m; int main() { scanf("%d%d", &n, &m); for (int i = n - 1; i >= 0; i--) { memset(b, 0, sizeof(b)); for (int j = 1; j <= 700; j++) b[j] = a[j] * (m - 1) / m + (a[j] * j / (j + 1) + 1.0 * j / 2 + a[j + 1] / (j + 1) + 1.0 * j / (j + 1)) / m; memcpy(a, b, sizeof(b)); } printf("%.10lf\n", a[1] * m); return 0; }
#include <bits/stdc++.h> using namespace std; int n; double f[2][605], k; int main() { cin >> n >> k; for (int i = 1; i <= n; i++) for (int j = 1; j <= 600; j++) f[i & 1][j] = (1.0 / k) * ((j * f[i & 1 ^ 1][j] + f[i & 1 ^ 1][j + 1] + j) / (j + 1) + (k - 1) * f[i & 1 ^ 1][j] + j / 2.0); printf("%.9f\n", k * f[n & 1][1]); }
#include <bits/stdc++.h> using namespace std; const int N = 605; const double eps = 1e-50; double dp[2][N]; int main() { dp[0][1] = 1.0; double ans = 0.0, k; int n; scanf("%d%lf", &n, &k); for (int i = 1; i <= n; ++i) { for (int j = 0; j < N; ++j) ans += dp[(i - 1) & 1][j] * (j / 2.0 + j / (j + 1.0)); for (int j = N - 1; j >= 0; --j) { dp[i & 1][j] = dp[(i - 1) & 1][j] * (1.0 - 1.0 / (j + 1) / k); dp[i & 1][j + 1] += dp[(i - 1) & 1][j] / k / (j + 1.0); if (dp[i & 1][j] < eps) dp[i & 1][j] = 0.0; } } printf("%.10lf", ans); return 0; }
#include <bits/stdc++.h> using namespace std; int n, k; double f[2][850]; int main() { scanf("%d%d", &n, &k); int t = min(n, 800); int now = 1; for (int i = 1; i <= n; i++, now ^= 1) for (int j = t; j; j--) f[now][j] = ((f[now ^ 1][j + 1] + j) / (j + 1.0) + j * (f[now ^ 1][j] + (j + 1.0) / 2.0) / (j + 1.0)) / (k * 1.0) + (k - 1) * f[now ^ 1][j] / (k * 1.0); printf("%.10lf", k * f[now ^ 1][1]); }
#include <bits/stdc++.h> using namespace std; double f[1002][2]; int main() { int n, k; scanf("%d%d", &n, &k); int can = 1; for (int j = 1; j <= n; j++) { can = 1 - can; for (int i = 1; i <= 1000; i++) { f[i][can] = ((1.0 * i + f[i][1 - can] * i + (f[i + 1][1 - can])) / (i + 1) + 0.5 * i) / k + f[i][1 - can] * (k - 1) / k; } } printf("%.12lf\n", f[1][can] * k); }
#include <bits/stdc++.h> using namespace std; const int Maxn = 100000 + 10; int n, k; double F[2][800]; void solve() { scanf("%d%d", &n, &k); for (int i = 1; i <= n; i++) { int p = i % 2, c = p ^ 1; memset(F[p], 0, sizeof(F[p])); for (int j = 1; j <= 800; j++) { F[p][j] = 1.0 / (double)k * ((double)j / (double)(j + 1) * (F[c][j] + (double)(j + 1) / 2.0) + 1.0 / (double)(j + 1) * (F[c][j + 1] + (double)j)) + (double)(k - 1) / k * F[c][j]; } } double ans = F[n % 2][1] * (double)k; printf("%.9f\n", ans); } int main() { solve(); return 0; }
#include <bits/stdc++.h> using namespace std; const int MAGIC = 2000; long double f[MAGIC + 10], inv[MAGIC + 10]; int main() { int n, k; scanf("%d %d", &n, &k); for (int j = 1; j < MAGIC; j++) { f[j] = 0.0; inv[j] = 1.0 / j; } f[1] = 1.0; long double q = 1.0 / k; long double ans = 0.0; for (int it = 0; it < n; it++) { for (int j = MAGIC - 1; j >= 1; j--) { if (f[j] < 1e-100) { f[j] = 0.0; continue; } ans += f[j] * j * (0.5 + inv[j + 1]); long double u = f[j] * q * inv[j + 1]; f[j + 1] += u; f[j] -= u; } } printf("%.17lf\n", (double)ans); return 0; }
#include <bits/stdc++.h> using namespace std; template <typename T, typename U> std::istream& operator>>(std::istream& i, pair<T, U>& p) { i >> p.first >> p.second; return i; } template <typename T> std::istream& operator>>(std::istream& i, vector<T>& t) { for (auto& v : t) { i >> v; } return i; } template <typename T, typename U> std::ostream& operator<<(std::ostream& o, const pair<T, U>& p) { o << p.first << ' ' << p.second; return o; } template <typename T> std::ostream& operator<<(std::ostream& o, const vector<T>& t) { if (t.empty()) o << '\n'; for (size_t i = 0; i < t.size(); ++i) { o << t[i] << " \n"[i == t.size() - 1]; } return o; } template <typename T> using minheap = priority_queue<T, vector<T>, greater<T>>; template <typename T> using maxheap = priority_queue<T, vector<T>, less<T>>; template <typename T> bool in(T a, T b, T c) { return a <= b && b < c; } unsigned int logceil(int first) { return 8 * sizeof(int) - __builtin_clz(first); } namespace std { template <typename T, typename U> struct hash<pair<T, U>> { hash<T> t; hash<U> u; size_t operator()(const pair<T, U>& p) const { return t(p.first) ^ (u(p.second) << 7); } }; } // namespace std template <typename T, typename F> T bsh(T l, T h, const F& f) { T r = -1, m; while (l <= h) { m = (l + h) / 2; if (f(m)) { l = m + 1; r = m; } else { h = m - 1; } } return r; } template <typename F> double bshd(double l, double h, const F& f, double p = 1e-9) { unsigned int r = 3 + (unsigned int)log2((h - l) / p); while (r--) { double m = (l + h) / 2; if (f(m)) { l = m; } else { h = m; } } return (l + h) / 2; } template <typename T, typename F> T bsl(T l, T h, const F& f) { T r = -1, m; while (l <= h) { m = (l + h) / 2; if (f(m)) { h = m - 1; r = m; } else { l = m + 1; } } return r; } template <typename F> double bsld(double l, double h, const F& f, double p = 1e-9) { unsigned int r = 3 + (unsigned int)log2((h - l) / p); while (r--) { double m = (l + h) / 2; if (f(m)) { h = m; } else { l = m; } } return (l + h) / 2; } template <typename T> T gcd(T a, T b) { if (a < b) swap(a, b); return b ? gcd(b, a % b) : a; } template <typename T> class vector2 : public vector<vector<T>> { public: vector2() {} vector2(size_t a, size_t b, T t = T()) : vector<vector<T>>(a, vector<T>(b, t)) {} }; template <typename T> class vector3 : public vector<vector2<T>> { public: vector3() {} vector3(size_t a, size_t b, size_t c, T t = T()) : vector<vector2<T>>(a, vector2<T>(b, c, t)) {} }; template <typename T> class vector4 : public vector<vector3<T>> { public: vector4() {} vector4(size_t a, size_t b, size_t c, size_t d, T t = T()) : vector<vector3<T>>(a, vector3<T>(b, c, d, t)) {} }; template <typename T> class vector5 : public vector<vector4<T>> { public: vector5() {} vector5(size_t a, size_t b, size_t c, size_t d, size_t e, T t = T()) : vector<vector4<T>>(a, vector4<T>(b, c, d, e, t)) {} }; class TaskD { public: void solve(istream& cin, ostream& cout) { int N, K; cin >> N >> K; int s = 1000; vector<double> D(N + 1, 0), E = D; double KK = 1.0 / K; E[0] = 1; double ans = 0; for (int l = 1; l < s; ++l) { double z = ((K - 1) + l / double(l + 1)); double second = 1.0 / l; for (int t = 0; t <= min(N, l - 2); ++t) E[t] = 0; for (int t = 1; t <= N; ++t) { if (t <= l - 2) { continue; } E[t] = KK * (E[t - 1] * z + D[t - 1] * second); if (E[t] < 1e-300) E[t] = 0; } double tt = 0; for (int t = 0; t < N; ++t) tt += E[t]; ans += tt * l * (0.5 + 1.0 / (l + 1)); swap(E, D); E[0] = 0; } cout << fixed << setprecision(10) << ans << endl; } }; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); TaskD solver; std::istream& in(std::cin); std::ostream& out(std::cout); solver.solve(in, out); return 0; }
#include <bits/stdc++.h> using namespace std; const int maxn = 100001; const int inf = 1 << 29; const int mod = 1000000007; const double eps = 1e-8; const int li = 700; int n, m; double ch; double dp[2][li + 2]; int main() { scanf("%d%d", &n, &m); ch = 1.0 / m; int pt = 1; for (int i = 1; i <= n; i++) { for (int j = 1; j <= li; j++) { double f = j / (j + 1.0); dp[pt][j] = (f * ch + 1 - ch) * dp[pt ^ 1][j] + ch * (1 - f) * dp[pt ^ 1][j + 1] + f * ch + j / 2.0 / m; } pt ^= 1; } printf("%.10f\n", m * dp[pt ^ 1][1]); }