Submission #1279111

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279111		dosts	Asceticism (JOI18_asceticism)	C++20	0 / 100	1 ms	568 KiB

asceticism

#include <bits/stdc++.h>
#pragma GCC optimize("O3,Ofast,unroll-loops")
#pragma GCC target("avx2")
#define int long long
#define pii pair<int,int>
#define vi vector<int>
#define ff first
#define ss second
#define sp << " " <<
#define all(x) x.begin(),x.end()
#define big(x) ((int)(x.size()))
using namespace std;
const int MOD = 1e9+7, LIM = 1e6+1, inf = 2e9;

const int N = 1e5+1;
int add(int x,int y) {
    if ((x + y) >= MOD) return x + y - MOD;
    return x + y;
}

int mult(int x,int y) {
    return (1LL * x * y) % MOD;
}

int expo(int x,int y) {
    if (!y) return 1;
    int e = expo(x, y >> 1);
    e = mult(e, e);
    if (y & 1) e = mult(e, x);
    return e;
}

void solve() {
    int n,k;
    cin >> n >> k;
    k--;
    k = min(k,n-k);
    vi dp(n+1,0),dp2(n+1,0);
    dp2[0] = 1;
    for (int i = 1;i<=n;i++) {
        dp[0] = 1;
        for (int j = 1;j<=i && j <= k;j++) {
            dp[j] = add(mult(dp2[j],j+1),mult(dp2[j-1],i-j));
        }
        dp.swap(dp2);
    }
    cout << dp2[k] << '\n';
}   

signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    #ifdef Dodi
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    #endif
    int t = 1;
    //cin >> t;
    while (t --> 0) solve();
}

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