```cpp
#include<bits/stdc++.h>
using namespace std;
int fa[5005];
double vis[5005];
struct node{
int from, to, w;
};
vector<node> edge;
int find(int x){
if(fa[x] == x){
return x;
}
return (fa[x] = find(fa[x]));
}
void com(int a, int b){
if(find(a) != find(b)){
fa[a] = b;
}
}
bool cmp(node x, node y){
return x.w < y.w;
}
int main()
{
int n, m;
cin >> n >> m;
for(int i = 0; i < n; i++){
fa[i] = i;
}
for(int i = 0; i < m; i++){
int a, b, c;
cin >> a >> b >> c;
edge.push_back({a, b, c});
// com(a, b);
}
sort(edge.begin(), edge.end(), cmp);
int ans = 0, num = 0;
for(int i = 0; i < m; i++){
if(find(edge[i].from) != find(edge[i].to)){
com(find(edge[i].to), find(edge[i].from));
num++;
ans += edge[i].w;
if(num == n - 1) break;
// cout << ans << " " << edge[i].w << endl;
}
}
if(num != n - 1) cout << "orz";
else cout << ans;
return 0;
}
```
改了第47行：
`com(find(edge[i].to),find(edge[i].from));`
by panxz2009 @ 2024-01-28 15:36:34
@[Lemon_zqp](/user/551630) 亲测能过
by panxz2009 @ 2024-01-28 15:37:11
@[panxz2009](/user/169326) dalao,为啥要这么改啊……
by Lemon_zqp @ 2024-01-28 16:36:16
```cpp
#include<bits/stdc++.h>
using namespace std;
int fa[5005];
double vis[5005];
struct node{
int from, to, w;
};
vector<node> edge;
int find(int x){
if(fa[x] == x){
return x;
}
return (fa[x] = find(fa[x]));
}
void com(int a, int b){
if(find(a) != find(b)){
//fa[a] = b; //事实上是这一句有问题
fa[find(a)]=fa[find(b)];
}
}
bool cmp(node x, node y){
return x.w < y.w;
}
int main()
{
int n, m;
cin >> n >> m;
for(int i = 1; i <= n; i++){
fa[i] = i;
}
for(int i = 0; i < m; i++){
int a, b, c;
cin >> a >> b >> c;
edge.push_back({a, b, c});
// com(a, b);
}
sort(edge.begin(), edge.end(), cmp);
int ans = 0, num = 0;
for(int i = 0; i < m; i++){
if(find(edge[i].from) != find(edge[i].to)){
com(edge[i].to, edge[i].from);
num++;
ans += edge[i].w;
if(num == n - 1) break;
// cout << ans << " " << edge[i].w << endl;
}
}
if(num != n - 1) cout << "orz";
else cout << ans;
return 0;
}
```
by panxz2009 @ 2024-01-28 18:04:54
@[Lemon_zqp](/user/551630)
by panxz2009 @ 2024-01-28 18:07:21
我一开始那样改的话就是对于同一条边调用了两次 `find` 函数，第二次调用，也就是 $21$ 行，反正是这个集合的父节点找自己，不影响，所以能过
by panxz2009 @ 2024-01-28 18:11:24