LOOPS

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<cmath>
 4 #define EPS 1e-8
 5 #define N 1005
 6 #define INF 1000005
 7 using namespace std;
 8 int n,m;
 9 double mp[N][N][3];
10 double dp[N][N];
11 int main(void){
12     while(~scanf("%d%d",&n,&m)){
13         memset(dp,0,sizeof(dp));
14         for(int i=0;i<n;++i)
15         for(int j=0;j<m;++j)
16         for(int k=0;k<3;++k)
17             scanf("%lf",&mp[i][j][k]);
18         for(int i=n-1;i>=0;--i)
19         for(int j=m-1;j>=0;--j){
20             if(i==n-1&&j==m-1)continue;
21             if(fabs(1-mp[i][j][0])<EPS)dp[i][j]=INF;
22             else dp[i][j]=(2+dp[i][j+1]*mp[i][j][1]+dp[i+1][j]*mp[i][j][2])/(1-mp[i][j][0]);
23         }
24         printf("%.3lf\n",dp[0][0]);
25     }
26 }