POJ 3071 Football(概率DP)

#include <cstdio>
#include <cstring>
#include <iostream>
#include <cmath>
#include <algorithm>
using namespace std;
double dp[501][501];
double p[501][501];
int main()
{
int n,i,j,mod,c,k,ans;
double maxz;
while(scanf("%d",&n)!=EOF)
{
if(n < 0) break;
for(i = 0;i < (1<<n);i ++)
{
for(j = 0;j < (1<<n);j ++)
{
scanf("%lf",&p[i][j]);
}
}
for(i = 0;i < (1<<n);i ++)
{
dp[0][i] = 1;
}
for(i = 1;i <= n;i ++)
{
for(j = 0;j < (1<<n);j ++)
dp[i][j] = 0;
}
for(i = 1;i <= n;i ++)
{
for(j = 0;j < (1<<n);j ++)
{
mod = j%(1<<i);
if(mod >= (1<<(i-1)))
{
c = (j/(1<<i))*(1<<i);
for(k = 0;k < (1<<(i-1));k ++)
{
dp[i][j] += dp[i-1][j]*dp[i-1][c+k]*p[j][c+k];
}
}
else
{
c = (j/(1<<i))*(1<<i)+(1<<(i-1));
for(k = 0;k < (1<<(i-1));k ++)
{
dp[i][j] += dp[i-1][j]*dp[i-1][c+k]*p[j][c+k];
}
}
}
}
ans = 0;maxz = 0;
for(i = 0;i < (1<<n);i ++)
{
if(maxz < dp
[i])
{
ans = i;
maxz = dp
[i];
}
}
printf("%d\n",ans+1);
}
return 0;
}