描述

What is possibility of rolling N dice and the sum of the numbers equals to M?

输入

Two integers N and M. (1 ≤ N ≤ 100, 1 ≤ M ≤ 600)

输出

Output the possibility in percentage with 2 decimal places.

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

double dp[][];

int main() {

#ifndef ONLINE_JUDGE

    freopen("input.txt", "r", stdin);

#endif

    int n, m;

    scanf("%d%d", &n, &m);

    memset(dp, , sizeof(dp));

    for (int i = ; i <= ; i++) {

        dp[][i] = 1.0 / 6.0;

    }

    for (int i = ; i <= n; i++) {

        for (int j = i; j <=  * i; j++) {

            double tmp = ;

            for (int k = ; k <= ; k++) {

                tmp += dp[i - ][j - k];

            }

            tmp /= 6.0;

            dp[i][j] = tmp;

        }

    }

    printf("%.2lf\n", dp[n][m] * );

    return ;

}