BZOJ 1491 [NOI2007]社交网络

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int maxn=109;
const int oo=1000000000;

int n,m;

int d[maxn][maxn];
long long c[maxn][maxn];

int main(){
	scanf("%d%d",&n,&m);
	
	for(int i=1;i<=n;++i){
		for(int j=1;j<=n;++j){
			d[i][j]=oo;
		}
	}
	for(int i=1;i<=n;++i)d[i][i]=0;
	
	while(m--){
		int x,y,z;
		scanf("%d%d%d",&x,&y,&z);
		d[x][y]=d[y][x]=z;
		c[x][y]=c[y][x]=1;
	}
	
	for(int k=1;k<=n;++k){
		for(int i=1;i<=n;++i){
			for(int j=1;j<=n;++j){
				if((i==j)||(i==k)||(j==k))continue;
				if(d[i][k]+d[k][j]<d[i][j]){
					d[i][j]=d[i][k]+d[k][j];
					c[i][j]=c[i][k]*c[k][j];
				}else if(d[i][k]+d[k][j]==d[i][j]){
					c[i][j]+=c[i][k]*c[k][j];
				}
			}
		}
	}
	
	for(int k=1;k<=n;++k){
		double ans=0;
		for(int i=1;i<=n;++i){
			for(int j=1;j<=n;++j){
				if((i==j)||(i==k)||(j==k))continue;
				if(d[i][k]+d[k][j]==d[i][j]){
					ans+=1.0*c[i][k]*c[k][j]/c[i][j];
				}
			}
		}
		printf("%.3f\n",ans);
	}
	return 0;
}