BZOJ 1491 社交网络

floyd。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxv 150
#define inf 1000000007
using namespace std;
int n,m,x,y;
double map[maxv][maxv],z,g[maxv][maxv];
int main()
{
    scanf("%d%d",&n,&m);
    for (int i=1;i<=n;i++)
        for (int j=1;j<=n;j++)
        {
            if (i==j) {map[i][j]=0;g[i][j]=1;}
            else {map[i][j]=inf;g[i][j]=0;}
        }
    for (int i=1;i<=m;i++)
    {
        scanf("%d%d%lf",&x,&y,&z);
        map[x][y]=map[y][x]=z;
        g[x][y]=g[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 (map[i][j]>map[i][k]+map[k][j])
                {
                    map[i][j]=map[i][k]+map[k][j];
                    g[i][j]=g[i][k]*g[k][j];
                }
                else if (map[i][j]==map[i][k]+map[k][j]) 
                        if ((i!=k) && (j!=k))
                            g[i][j]+=g[i][k]*g[k][j];
            }
    for (int i=1;i<=n;i++)
    {
        double ans=0;
        for (int j=1;j<=n;j++)
            for (int k=1;k<=n;k++)
            {
                if ((i!=j) && (i!=k))
                {
                    if (map[j][i]+map[i][k]==map[j][k])
                        ans+=(g[j][i]*g[i][k])/g[j][k];        
                }
            }
        printf("%.3lf\n",ans);
    }
    return 0;
}