概率 数学期望 HDU - 5245

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <math.h>
using namespace std;

int main()
{
int t;
scanf("%d",&t);
int m,n,k;
for(int CASE=1;CASE<=t;CASE++){
scanf("%d%d%d",&m,&n,&k);
double ans = 0;
for(int i=1;i<=m;i++){
for(int j=1;j<=n;j++){
double x = (1.0-((i-1)*(i-1)+(m-i)*(m-i))/(double)(m*m))*(1.0-((j-1)*(j-1)+(n-j)*(n-j))/(double)(n*n));
ans+=1-pow(1.0-x,(double)k);
}
}
printf("Case #%d: %d\n",CASE,(int)round(ans));
}
return 0;
}