GCJ 2008 APAC local onsites C Millionaire

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;

double dp[20][50000];
int T;
int M;
int X;
double P;

void work()
{
memset(dp,0,sizeof dp);
dp[0][1<<M]=1.00;
for(int r=1; r<=M; r++)
{
for(int j=0; j<=(1<<M); j++)
{
double ans=0;
for(int k=0;; k++)
{
if(j+k>(1<<M)||j-k<0) break;
ans=max(ans,P*dp[r-1][j+k]+(1-P)*dp[r-1][j-k]);
}
dp[r][j]=ans;
}
}
}

int main()
{
//freopen("C-large-practice.in","r",stdin);
// freopen("C-large-practice.out","w",stdout);

scanf("%d",&T);
for(int Case=1; Case<=T; Case++)
{
scanf("%d%lf%d",&M,&P,&X);
work();
long long XX=(long long)X;
int d=(1<<M);
long long dd=(long long)d;
long long RR=XX*dd/(long long)1000000;
int R=int(RR);
printf("Case #%d: %6lf\n",Case,dp[M][R]);
}
return 0;
}