Submission #487611

#	Time	Username	Problem	Language	Result	Execution time	Memory
487611		KazamaHoang	Zapina (COCI20_zapina)	C++14	110 / 110	141 ms	1292 KiB

zapina

#include <bits/stdc++.h>

using namespace std;

const int MOD = 1e9 + 7;

int binpow(int a, int b) {
    int c = 1;
    while (b) {
        if (b & 1)
            c = (long long)c * a % MOD;
        b >>= 1;
        a = (long long)a * a % MOD;
    }
    return c;
}

int ckn[355][355];

void init(int n) {
    for (int i = 0; i <= n; ++ i) {
        ckn[0][i] = 1;
        for (int j = 1; j <= i; ++ j) 
            ckn[j][i] = (ckn[j-1][i-1] + ckn[j][i-1]) % MOD;
    }
}

int n;

int un_happy() {
    vector<vector<int>> dp(n+5, vector<int> (n+5, 0));
    dp[0][0] = 1;
    for (int i = 1; i <= n; ++ i) 
        for (int j = 0; j <= n; ++ j) 
            for (int k = 0; k <= j; ++ k) 
                if (k != i) {
                    dp[i][j] += (long long)dp[i-1][j-k] * ckn[k][j] % MOD; 
                    dp[i][j] %= MOD;
                }
    return dp[n][n];
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin >> n;
    init(n);
    cout << (binpow(n, n) - un_happy() + MOD) % MOD;
    return 0;
}

• Subtask 1: 22 / 22
• Subtask 2: 33 / 33
• Subtask 3: 55 / 55