제출 #725424

#제출 시각아이디문제언어결과실행 시간메모리
725424colossal_pepe수열 (APIO14_sequence)C++17
33 / 100
3 ms724 KiB
#include <iostream> #include <deque> #include <algorithm> #include <cstring> using namespace std; // l[n] is bad if l[n - 1] intersects l[n + 1] before l[n] does // => l[0] is bad if l[1] intersects l[-1] before l[0] does using ll = long long; const int N = 500; const int K = 200; int n, k, par[K + 5][N + 5]; ll a[N + 5], pfx_sum[N + 5], dp[N + 5]; deque<int> l; ll ps(int i) { return pfx_sum[i]; } ll ss(int i) { return pfx_sum[n] - pfx_sum[i - 1]; } ll f(int li, ll x) { return -ps(li) * x + dp[li]; } bool firstIsBad(int l1, int l2, int l0) { ll m1 = -ps(l1), c1 = dp[l1]; ll m2 = -ps(l2), c2 = dp[l2]; ll m0 = -ps(l0), c0 = dp[l0]; return (c2 - c0) * (m0 - m1) > (c1 - c0) * (m0 - m2); // ((c2 - c0) / (m0 - m2)) > ((c1 - c0) / (m0 - m1)) } void dfs(int i, int s) { cout << i << ' '; if (s > 1) dfs(par[s][i], s - 1); } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cin >> n >> k; a[0] = pfx_sum[0] = 0; for (int i = 1; i <= n; i++) { cin >> a[i]; pfx_sum[i] = a[i] + pfx_sum[i - 1]; } memset(par, -1, sizeof par); for (int s = 1; s <= k; s++) { deque<int> l_new; for (int i = n; i >= 1; i--) { dp[i] = -1; while (l.size() > 1 and (i <= l[0] or f(l[0], ss(i + 1)) <= f(l[1], ss(i + 1)))) l.pop_front(); if (s == 1) dp[i] = ps(i) * ss(i + 1); else if (not l.empty() and l[0] < i) { dp[i] = ps(i) * ss(i + 1) + f(l[0], ss(i + 1)); par[s][i] = l[0]; } if (dp[i] == -1) continue; while (l_new.size() > 1 and firstIsBad(l_new[0], l_new[1], i)) l_new.pop_front(); l_new.push_front(i); } reverse(l_new.begin(), l_new.end()); l = l_new; } ll ans = 1; for (int i = 1; i <= n; i++) { if (dp[ans] < dp[i]) ans = i; } cout << dp[ans] << '\n'; dfs(ans, k); cout << '\n'; return 0; }
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