#include<bits/stdc++.h>
#define M 2147483647
using namespace std;
struct node
{
	int u,v,w;
}a[200001];
int f[5001],n,m,ans;
bool b[5001];
inline int read()
{
	int x=0,f=1;
	char c=getchar();
	while(c<'0'||c>'9')
	{
		if(c=='-') f=-1;
		c=getchar();
	}
	while(c>='0'&&c<='9')
	x=(x<<3)+(x<<1)+(c^48),c=getchar();
	return x*f;
}
inline int findfather(int x)
{
	if(f[x]==x) return x;
	return f[x]=findfather(f[x]);
}
inline bool cmp(node x,node y)
{
	return x.w<y.w;
}
void kruskal()
{
	int sum=0;
	sort(a+1,a+m+1,cmp);
	for(register int i=1;i<=m;++i)
	{
		int fu=findfather(a[i].u),fv=findfather(a[i].v);
		if(fu==fv) continue;
		ans+=a[i].w,f[fu]=fv;
		if(++sum==n-1) break;
	}
}
int main()
{
	n=read(),m=read();
	for(register int i=1;i<=n;++i) f[i]=i;
	for(register int i=1;i<=m;++i)
	a[i].u=read(),a[i].v=read(),a[i].w=read();
	kruskal();
	printf("%d\n",ans);
	return 0;
}

码风优良

这个判断输出orz怎么弄我竟然想泛洪