洛谷P2047||bzoj1491 [NOI2007]社交网络

https://www.luogu.org/problemnew/show/P2047

https://www.lydsy.com/JudgeOnline/problem.php?id=1491

也可以用floyed做掉

 #include<cstdio>
 #include<algorithm>
 #include<cstring>
 #include<vector>
 using namespace std;
 #define fi first
 #define se second
 #define mp make_pair
 #define pb push_back
 typedef long long ll;
 typedef unsigned long long ull;
 typedef pair<int,int> pii;
 ll n,m;
 ll a[][],d[][];
 ll n1[][];//最短路计数
 double an[];
 int main()
 {
     ll i,j,k,x,y,z;
     scanf("%lld%lld",&n,&m);
     memset(a,0x3f,sizeof(a));
     for(i=;i<=n;++i)
         a[i][i]=;
     for(i=;i<=m;++i)
     {
         scanf("%lld%lld%lld",&x,&y,&z);
         a[x][y]=a[y][x]=min(a[x][y],z);
     }
     memcpy(d,a,sizeof(d));
     for(i=;i<=n;++i)
         for(j=;j<=n;++j)
             n1[i][j]=;
     for(k=;k<=n;++k)
         for(i=;i<=n;++i)
             for(j=;j<=n;++j)
                 if(i!=k&&i!=j&&k!=j)
                 {
                     if(d[i][j]>d[i][k]+d[k][j])
                     {
                         d[i][j]=d[i][k]+d[k][j];
                         n1[i][j]=n1[i][k]*n1[k][j];
                     }
                     else if(d[i][j]==d[i][k]+d[k][j])
                     {
                         n1[i][j]+=n1[i][k]*n1[k][j];
                     }
                 }
     //for(i=1;i<=n;++i)
     //    for(j=1;j<=n;++j)
     //        printf("1t%lld %lld %lld %lld\n",i,j,d[i][j],n1[i][j]);
     for(i=;i<=n;++i)
     {
         for(j=;j<=n;++j)
             for(k=;k<=n;++k)
                 if(i!=j&&j!=k&&i!=k)
                 {
                     if(d[j][i]+d[i][k]==d[j][k])
                     {
                         an[i]+=double(n1[j][i])*n1[i][k]/n1[j][k];
                     }
                 }
         printf("%.3f\n",an[i]);
     }
     return ;
 }