poj3723 最大权森林

3723

题目大意:自己看

分析：最后答案就是10000*(n+m)-所有人加进来能获得的最大权值和，把权值取负就是求最小生成树了，节点编号是从0开始的- -

#include <iostream>
#include <cstdio>
#include <cstring>
#include <set>
#include <algorithm>
#include <map>
#include <queue>
#include<vector>
#define maxn 20010
#define maxm 50010
#define INF 0x3fffffff
using namespace std;
struct edge{
    int u,v,cost;
    edge(){}
    edge(int _u,int _v,int _cost){
        u=_u;v=_v;cost=_cost;
    }
};
bool cmp(edge a,edge b){
    return a.cost<b.cost;
}
int V,E;
int father[maxn];
void init(){
    for(int i=0;i<=V;++i){
        father[i]=i;
    }
}
int Find(int x){
    return father[x]==x?x:father[x]=Find(father[x]);
}
void Union(int x,int y){
    x = Find(x);
    y = Find(y);
    if(x!=y)father[x]=y;
}
bool same(int x,int y){
    return Find(x)==Find(y);
}
edge G[maxm];
int cnt=0;
void addedge(int u,int v,int cost){
    G[cnt++]=edge(u,v,cost);
}
int kruskal(){
    sort(G,G+cnt,cmp);
    init();
    int ans=0;
    for(int i=0;i<cnt;++i){
        edge e = G[i];
        if(!same(e.u,e.v)){
            Union(e.u,e.v);
            ans+=e.cost;
        }
    }
    return ans;
}
int n,m,R;
int main (){
    int t;
    scanf("%d",&t);
    while(t--){
        scanf("%d%d%d",&n,&m,&R);
        cnt=0;
        V=n+m;
        for(int i=0;i<R;++i){
            int u,v,w;
            scanf("%d%d%d",&u,&v,&w);
            addedge(u,v+n,-w);
        }
        printf("%d
",(n+m)*10000+kruskal());
    }
}