Submission #1834843

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Source Code Expand

#include <iostream>
#include <vector>
#include <deque>
#include <math.h>
#include <set>
#include <iomanip>
#include <time.h>
#include <list>
#include <stdio.h>
#include <queue>
#include <map>
#include <algorithm>
#include <assert.h>
#include <memory.h>

#define mk make_pair
#define sc second
#define fr first
#define pb emplace_back
#define all(s) s.begin(), s.end()
#define sz(s) ( (int)s.size() )

using namespace std;

const int N = 305, mod = 1e9 + 7;

int n, m;
long long dp[N][N][N];

main ()
{
    cin >> n >> m;
    dp[0][1][1] = 1;
    for (int i = 0; i <= m; i++)
    {
        for (int j = 0; j <= n; j++)
        {
            for (int k = 0; k <= j; k++)
            {
                dp[i + 1][j + 1][k] += dp[i][j][k] * (n - j);
                dp[i + 1][j + 1][k] %= mod;

                dp[i + 1][j][k] += dp[i][j][k] * (j - k);
                dp[i + 1][j][k] %= mod;

                dp[i + 1][j][j] += dp[i][j][k] * k;
                dp[i + 1][j][j] %= mod;
            }
        }
    }
    cout << dp[m][n][n] << endl;
}

Submission Info

Judge Result