Submission #1306922

#	Time	Username	Problem	Language	Result	Execution time	Memory
1306922		Double_Slash	Asceticism (JOI18_asceticism)	C++20	49 / 100	1094 ms	1016 KiB

asceticism

#pragma GCC optimize("Ofast,unroll-loops,inline")
#include <bits/stdc++.h>
#pragma GCC target("avx2")

using namespace std;
using ll = long long;

const int M = 1e9 + 7;

int N, K;
ll dp[100000]{1}, dp2[100000]{1};

int main() {
    cin >> N >> K;
    for (int n = 1; n <= N;) {
        for (int k = n; k > 0; --k) {
            dp2[k] = (dp[k] * (k + 1) + dp[k - 1] * (n - k)) % M;
        }
        if (n++ == N) cout << dp2[K - 1];
        for (int k = n; k > 0; --k) {
            dp[k] = (dp2[k] * (k + 1) + dp2[k - 1] * (n - k)) % M;
        }
        if (n++ == N) cout << dp[K - 1];
    }
}

• Subtask 1: 4 / 4
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 0 / 51