Codeforces Beta Round #16 (Div. 2 Only), problem: (E) Fish 機率DP

#include<cstdio>#include<cstring>const int LMT=(1<<18)+10;double dp[LMT],a[19][19],__one[LMT];void get_one(void){int i,x;for(i=1;i<LMT;i++){x=i;while(x){if(x&1)__one[i]++;x>>=1;}}}int main(void){int n,lim,i,ii,jj;get_one();while(~scanf("%d",&n)){memset(dp,0,sizeof(dp));     lim=(1<<n)-1;     dp[lim]=1.0; for(ii=0;ii<n;ii++) for(jj=0;jj<n;jj++) scanf("%lf",&a[ii][jj]); for(i=lim-1;i>0;i--) if(__one[i]>0) { for(jj=0;jj<n;++jj) if(!(i&(1<<jj))) for(ii=0;ii<n;++ii) if(i&(1<<ii)) dp[i]+=a[ii][jj]*dp[i|(1<<jj)]; dp[i]/=(__one[i]+1)*__one[i]*0.5; } for(i=0;i<n;i++) printf("%.6lf ",dp[1<<i]); printf("\n");}return 0;}