hdu1102

将已有边权设为零，再跑kruskal……

#include<bits/stdc++.h>
using namespace std;
#define int long long
const int maxn=50000;
struct node{
    int x,y,z;
}a[maxn];
int n,q,cnt;
int fa[maxn];
int cmp(node x,node y){
    return x.z<y.z;
}
int find(int x){
    if(fa[x]==x)return x;
    return fa[x]=find(fa[x]);
}
signed main(){
    while(scanf("%lld",&n)!=EOF){
        int x,y;
        cnt=0;
        for(int i=1;i<=n;i++)
            fa[i]=i;
        for(int i=1;i<=n;i++)
            for(int j=1;j<=n;j++){
                scanf("%lld",&x);
                a[++cnt]=(node){i,j,x};
            }
        cin>>q;
        for(int i=1;i<=q;i++){
            scanf("%lld%lld",&x,&y);
            a[(x-1)*n+y].z=0;
            a[(y-1)*n+x].z=0;
            //if(find(x)!=find(y))
            //    fa[find(x)]=find(y);
        }
        sort(a+1,a+1+cnt,cmp);
        int edge=0,tot=0;
        for(int i=1;i<=cnt;i++){
            x=a[i].x,y=a[i].y;
            if(find(x)!=find(y)){
                fa[find(x)]=find(y);
                tot+=a[i].z;
                edge++;
            }
            if(edge==n-1)break;
        }
        printf("%lld\n",tot);
    }
    return 0;
}
/*
3
0 990 692
990 0 179
692 179 0
1
1 2
*/