普及组模板——最小生成树

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
inline int read(){
    int t=1,num=0;char c=getchar();
    while(c>‘9‘||c<‘0‘){if(c==‘-‘)t=-1;c=getchar();}
    while(c>=‘0‘&&c<=‘9‘){num=num*10+c-‘0‘;c=getchar();}
    return num*t;
}
const int N=5010,M=200010;
struct edge{int f,t,c;}e[M];
bool cmp(edge a,edge b){return a.c<b.c;}
int fa[N],n,m,ans=0,cnt=1;
void init(){
    for(int i=1;i<=n;i++)fa[i]=i;
}
int find(int x){
    return x==fa[x]?x:fa[x]=find(fa[x]);
}
void unite(int x,int y){
    x=find(x);y=find(y);
    if(x==y)return;
    fa[x]=y;
}
void kru(){
    sort(e+1,e+1+m,cmp);
    for(int i=1;i<=m;i++){
        if(cnt==n)break;
        if(find(e[i].f)==find(e[i].t))continue;
        unite(e[i].f,e[i].t);ans+=e[i].c;cnt++;
    }
}
int main()
{
    n=read();m=read();init();
    for(int i=1;i<=m;i++){
        int x=read(),y=read(),z=read();
        e[i].f=x;e[i].t=y;e[i].c=z;
    }
    kru();
    if(cnt==n)printf("%d\n",ans);
    else puts("orz");
    return 0;
}