zoj 3640 Help Me Escape 概率DP

记忆化搜索+概率DP

代码如下：

 #include<iostream>
 #include<stdio.h>
 #include<algorithm>
 #include<iomanip>
 #include<cmath>
 #include<cstring>
 #include<vector>
 #define ll __int64
 #define pi acos(-1.0)
 #define MAX 50000
 using namespace std;
 int c[],n,ff;
 double dp[];
 double solve(int f)
 {
     if(dp[f]>) return dp[f];
     dp[f]=;
     for(int i=;i<n;i++){
         if(f>c[i]){
             double t=(sqrt(5.0)+1.0)/*c[i]*c[i];
             int p=(int)t;
             dp[f]+=1.0*p/n;
         }
         else{
             dp[f]+=(+solve(f+c[i]))/n;
         }
     }
     return dp[f];
 }
 int main(){
     while(scanf("%d%d",&n,&ff)!=EOF){
         for(int i=;i<n;i++) cin>>c[i];
         memset(dp,,sizeof(dp));
         printf("%.3lf\n",solve(ff));
     }
 
     return ;
 }