[洛谷3366]【模板】最小生成树

思路：Kruskal

#include<cstdio>
#include<utility>
#include<algorithm>
#define w first
#define a second.first
#define b second.second
const int N=5001;
typedef std::pair<int,std::pair<int,int> > Edge;
class UnionFindSet {
    private:
        int anc[N];
    public:
        UnionFindSet(int n) {
            for(int i=1;i<=n;i++) anc[i]=i;
        }
        int Find(int x) {
            return (x==anc[x])?x:(anc[x]=Find(anc[x]));
        }
        void Union(int x,int y) {
            anc[Find(y)]=Find(x);
        }
};
int main() {
    int n,m;
    scanf("%d%d",&n,&m);
    Edge e[m];
    for(int i=0;i<m;i++) scanf("%d%d%d",&e[i].a,&e[i].b,&e[i].w);
    std::sort(&e[0],&e[m]);
    UnionFindSet s(n);
    int ans=0,area=n;
    for(int i=0;i<m;i++) {
        if(s.Find(e[i].a)==s.Find(e[i].b)) continue;
        ans+=e[i].w;
        s.Union(e[i].a,e[i].b);
        area--;
        if(area==1) {
            printf("%d
",ans);
            return 0;
        }
    }
    puts("orz");
    return 0;
}