洛谷——最小生成树模板

#include <cstdio>
#include <algorithm>
using namespace std;
const int maxn = 2000005;
const int maxx = 5005;
int root[maxx];
int find(int x){
return x==root[x]?x:root[x]=find(root[x]);
}
struct edge{
int u,v;
int cost;
bool operator <(const edge &b)const{
return cost < b.cost;
}
}E[maxn];
int main(){
int N,M;
scanf("%d%d",&N,&M);
for(int i = 0; i < M; i++){
scanf("%d%d%d",&E[i].u,&E[i].v,&E[i].cost);
}
sort(E,E+M);
for(int i = 1;i <= N; i++){
root[i] = i;
}
int total = 0;
for(int i=0;i<M;i++){
int faU = find(E[i].u);
int faV = find(E[i].v);
if(faU != faV){
root[faU] = faV;
total += E[i].cost;
}
}
printf("%d\n",total);
return 0;
}