UESTC 1703 Seven Dices

七个for。或者写成DP。

//#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<iostream>
#include<sstream>
#include<cmath>
#include<climits>
#include<string>
#include<map>
#include<queue>
#include<vector>
#include<stack>
#include<set>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define pb(a) push_back(a)
#define INF 0x1f1f1f1f
#define lson idx<<1,l,mid
#define rson idx<<1|1,mid+1,r
#define PI  3.1415926535898
template<class T> T min(const T& a,const T& b,const T& c) {
    return min(min(a,b),min(a,c));
}
template<class T> T max(const T& a,const T& b,const T& c) {
    return max(max(a,b),max(a,c));
}
#define clr0(a) memset(a,0,sizeof(a))
#define clr1(a) memset(a,-1,sizeof(a))
void debug(){
#ifdef ONLINE_JUDGE
#else
    freopen("d:\\in.txt","r",stdin);
   // freopen("d:\\out1.txt","w",stdout);
#endif
}
int getch()
{
    char ch;
//    while((ch=getchar())!=EOF)
//    {
//        if(ch!=' '&&ch!='\n')return ch;
//    }
    scanf(" %c",&ch);
    return ch;
}
int vis[50][10];
double dp[50][10];
double f(int n,int res)
{
    if(res==0)
    {
        if(n==0)return 1;
        else return 0;
    }
    if(vis[n][res])return dp[n][res];
    vis[n][res]=1;
    double x=0;
    for(int i=1;i<=6;i++)
    {
        if(n-i>=0)
            x+=f(n-i,res-1)/6;
    }
    return dp[n][res]=x;
}
int main()
{
    int n;
    while(scanf("%d",&n)!=EOF)
    {
        memset(vis,0,sizeof(dp));
        printf("%.4lf\n",f(n,7));
    }
    return 0;
}