Submission #993463

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Source Code Expand

import java.util.Scanner;

public class Main {
	public static long MOD = 1000000007;
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		long[][] dp = new long[n+1][n+1];
		dp[1][0] = 1;
		for(int i=0;i<m;i++) {
			long[][] next = new long[n+1][n+1];
			for(int a=0;a<=n;a++) {
				for(int b=0;b<=n;b++) {
					if (dp[a][b] == 0) continue;
					next[a+b][0] = (next[a+b][0] + dp[a][b] * a) % MOD;
					next[a][b+1] = (next[a][b+1] + dp[a][b] * (n-a-b)) % MOD;
					next[a][b] = (next[a][b] + dp[a][b] * b) % MOD;
				}
			}
			dp = next;
		}
		System.out.println(dp[n][0]);
	}

}

Submission Info

Judge Result