CF F. Royal Questions kruskal

Code:

#include<bits/stdc++.h>
#define ll long long
#define maxn 200004
using namespace std;
void setIO(string s) {
    string in=s+".in";
    freopen(in.c_str(),"r",stdin);
}
int n,m;
int p[maxn],tag[maxn];
void init() {
    for(int i=0;i<maxn;++i) p[i]=i;
}
int find(int x) {
    return p[x]==x?x:p[x]=find(p[x]);
}
struct Edge {
    int u,v,c;
}ed[maxn];
bool cmp(Edge a,Edge b) {
    return a.c>b.c;
}
int main() {
    // setIO("input");
    init();
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;++i) scanf("%d%d%d",&ed[i].u,&ed[i].v,&ed[i].c);
    sort(ed+1,ed+1+m,cmp);
    ll ans=0;
    for(int i=1;i<=m;++i) {
        int a=find(ed[i].u), b=find(ed[i].v);
        if(a!=b&&(!tag[a]||!tag[b])) ans+=1ll*ed[i].c, tag[a]|=tag[b], p[b]=a;
        else if(a==b && !tag[a]) ans+=1ll*ed[i].c, tag[a]=1;
    }
    printf("%I64d\n",ans);
    return 0;
}

原文地址：https://www.cnblogs.com/guangheli/p/11263392.html