@[xuan132](/user/582113) 并查集不是这么写的啊。
需要有 `getf` 函数：
```cpp
int getf(int x) { return f[x] == x ? f[x] : f[x] = getf(f[x]); }
```
by zhiyangfan @ 2021-12-20 21:25:21
@[xuan132](/user/582113) 兄弟你的并查集呢
by Universal_xtr @ 2021-12-20 22:01:00
@[xuan132](/user/582113) 要有找祖宗的`fa`函数吧。。。
`int fa(int x){return f[x]==x?x:f[x]=fa(f[x]);}`
by Universal_xtr @ 2021-12-20 22:02:30
@[xuan132](/user/582113)
```cpp
#include <iostream>
#include <algorithm>
#include <cstdio>
using namespace std;
struct bian
{
int head,tail,length;
};
bool cmp(bian x,bian y)
{
return x.length<y.length;
}
int v[10000];
int fa(int x){return v[x]==x?x:v[x]=fa(v[x]);}
long long sum=0,cnt=0;
bian l[1000000];
int main()
{
int n,m;cin>>n>>m;
for(int i=1;i<=m;i++)
{
cin>>l[i].head>>l[i].tail>>l[i].length;
}
sort(l+1,l+m,cmp);
for(int i=1;i<=n;i++)
{
v[i]=i;
}
for(int i=1;i<=m;i++)
{
int v1=fa(l[i].head),v2=fa(l[i].tail);
if(v1!=v2)
{
sum+=l[i].length;
v[v1]=v[v2];
cnt++;
if(cnt==n-1)
{
break;
}
}
}
if(cnt==n-1)
{
cout<<sum;
}
else
{
cout<<"orz";
}
return 0;
}
```
by Universal_xtr @ 2021-12-20 22:07:46
@[zhiyangfan](/user/137603) 谢谢大佬
by xuan132 @ 2021-12-20 22:59:06
@[Universal_xtr](/user/540148) 谢谢大佬，还帮忙改了，感激涕零
by xuan132 @ 2021-12-20 23:00:08
sort确定没有问题吗
我记得从1到m排序的话是
```
sort(a+1,a+1+m,cmp);
```
吧
by KS_tips_CN @ 2022-02-27 15:21:45