#include<bits/stdc++.h>
using namespace std;
struct Edge{int u,v,w;}edge[200005];
int fa[5005],n,m,ans,eu,ev,cnt;
inline bool cmp(Edge a,Edge b)
{
return a.w<b.w;
}
//快排的依据
inline int find(int x)
{
return fa[x]!=x?fa[x]=find(fa[x]):x;
}
//并查集循环实现模板,及路径压缩,不懂并查集的同学可以戳一戳代码上方的“并查集详解”
inline void kruskal()
{
sort(edge,edge+m,cmp);
//将边的权值排序
for(int i=0;i<m;i++)
{
eu=find(edge[i].u), ev=find(edge[i].v);
if(eu==ev)
{
continue;
}
//若出现环,则continue
ans+=edge[i].w;
//将此边权计入答案
fa[ev]=eu;
if(++cnt==n-1)
{
break;
}
//循环结束条件,及边数为点数减一时
}
}
int main()
{
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++)
{
fa[i]=i;
}
//初始化并查集
for(int i=0;i<m;i++)
{
scanf("%d%d%d",&edge[i].u,&edge[i].v,&edge[i].w);
}
kruskal();
printf("%d",ans);
return 0;
}
并查集模板
#include <bits/stdc++.h>
using namespace std;
int n,m;
int const maxn =10010;
int f[maxn];
int find_f(int x) {
return f[x]!=x?f[x]=find_f(f[x]):x;
}
void union_set(int x,int y) {
int rx = find_f(x);
int ry = find_f(y);
if(rx!=ry) {
f[ry] = rx;
}
}
bool query(int x,int y){
int rx = find_f(x);
int ry = find_f(y);
if(rx!=ry) return false;
return true;
}
int main() {
//freopen("in.txt","r",stdin);
cin>>n>>m;
int op,a,b;
for (int i=1;i<=n;i++) f[i] =i;
for (int i=0;i<m;i++) {
cin>>op>>a>>b;
if(op==1) {
union_set(a,b);
}
if(op==2) {
if(query(a,b)) cout<<"Y"<<endl;
else cout<<"N"<<endl;
}
}
//while(1){}
}