hdu 3853 LOOPS 概率DP

简单的概率DP入门题

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 1003
using namespace std;
struct point
{
    double c,b,r;
}p[MAX][MAX];
double dp[MAX][MAX];
int main(){
    int n,m,i,j;
    while(scanf("%d%d",&n,&m)!=EOF){
        for(i=1;i<=n;i++)
            for(j=1;j<=m;j++)
                scanf("%lf%lf%lf",&p[i][j].c,&p[i][j].r,&p[i][j].b);
        dp[n][m]=0.0;
        for(i=n;i>=1;i--)
        for(j=m;j>=1;j--){
            if(i==n&&j==m) continue;
            if(fabs(1-p[i][j].c)<1e-5) continue;
            dp[i][j]=(p[i][j].r*dp[i][j+1]+p[i][j].b*dp[i+1][j]+2)/(1-p[i][j].c);
        }
        printf("%.3lf
",dp[1][1]);
    }
    return 0;
}