M<=2e5
by hyx_0704 @ 2023-11-27 13:31:50
这个不re也是挺厉害的
by hyx_0704 @ 2023-11-27 13:32:30
@[hyx_0704](/user/574222) thx%%%
by Three_no @ 2023-11-27 13:40:56
@[hyx_0704](/user/574222) 请问怎么改呢
我把数组开大，但还是不行
```cpp
#include<cstdio>
#include<algorithm>
using namespace std;
int mincost,cost,s1;
int f[5010],s,t,j,n,m,ans;
int find(int x){
if(f[x]==x)return x;
return f[x]=find(f[x]);
}
struct Edge{
int a,b,w;
}edge[200005];
bool cmp(Edge a,Edge b){
return a.w<b.w;
}
int main(){
scanf("%d%d", &n, &m);
for(int i=1;i<=m;i++){
scanf("%d%d%d", &s, &t, &cost);
edge[i]={s,t,cost};
}
sort(edge+1,edge+1+j,cmp);
for(int i=1;i<=n;i++){
f[i]=i;
}
for(int i=1;i<=m;i++){
int fx=find(edge[i].a);
int fy=find(edge[i].b);
if(fx!=fy){
ans++;
mincost+=edge[i].w;
f[fx]=fy;
}
if(ans==n-1) break;
}
printf("%d",mincost);
return 0;
}
```
by Three_no @ 2023-11-27 13:45:36
注意看你的排序，+j是什么东西，j是0，等同于你没有排序
by c20220625 @ 2023-11-27 13:52:36
sort(e+1,e+m+1,cmp)
by hyx_0704 @ 2023-11-27 13:59:24
@[Rannan2000](/user/1044332)
建议编译开 -Wall 没用的变量会警告的
by hyx_0704 @ 2023-11-27 14:03:36
@[c20220625](/user/984018) @[hyx_0704](/user/574222) 谢谢
~~这个代码是我改的另一道题的代码，结果那里忘记改了（doge~~
by Three_no @ 2023-11-28 12:35:19