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<cstdio>

#include<cstdlib>

#include<iostream>

using namespace std;

double ans;

double a[],b[];

int n,m;

void getdp()

{

    for(int i=;i<=;i++) a[i]=;

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

        for(int j=m;j>=;j--)

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

          if(j-k>) b[j]+=a[j-k];

        for(int j=;j<=m;j++){

            a[j]=b[j];

            b[j]=;

        }

    }

}

int main()

{

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

    getdp();

    ans=1.0*a[m];

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

        ans/=6.0;

    }

    ans*=;

    printf("%.2lf\n",ans);

    return ;

}        

#include<cstdio>

#include<cstdlib>

#include<iostream>

using namespace std;

using namespace std;

double d[][];

int main()

{

    int n,m;

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

    memset(d,,sizeof d);

    d[][]=;

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

    {

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

        {

            for(int j=m;j>=k;j--)d[i][j]+=d[i-][j-k]/;

        }

    }

    printf("%0.2lf\n",d[n][m]*);

    return ;

}