Решение задачи Бросание кубика с Меньшиков

#include <iostream>
#include <cstdio>
#include <cmath>
 
using namespace std;
 
int n,sum;
void input()
{
    cin>>n>>sum;
 
}
const int MaxN = 500 + 2;
const int MaxSum = 3000 +2;
long double mem[MaxSum][MaxN];
 
void solve()
{
    mem[0][0] = 1;
    for (int curN = 1; curN <=n; curN++)
    {
        for (int curSum = 1; curSum<=sum; curSum++)
        {
            for (int prev = 1; prev<=6;prev++)
            {
                if (curSum - prev >= 0)
                    mem[curSum][curN] += mem[curSum-prev][curN-1] / 6.0;
            }
        }
    }
    cout<<mem[sum][n];
}
int main()
{
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
 
    input();
    solve();
    return 0;
}