Submission #992349

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

#define fi first
#define se second
#define mp make_pair
#define pb push_back

#define P 1000000007

#define N 310
int n, m;
int f[N][N][N];

int main() {
	cin >> n >> m;
	f[0][1][0] = 1;
	for (int i = 0; i < m; i ++)
		for (int j = 1; j <= n; j ++)
			for (int k = 0; k <= n-j; k ++) if (f[i][j][k]) {
				(f[i+1][j+k][0] += (ll)f[i][j][k]*j%P) %= P;
				(f[i+1][j][k] += (ll)f[i][j][k]*k%P) %= P;
				(f[i+1][j][k+1] += (ll)f[i][j][k]*(n-j-k)%P) %= P;
			}
	cout << f[m][n][0] << endl;
	return 0;
}

Submission Info

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