bzoj1682 [Usaco2005 Mar]Out of Hay 干草危机（kruskal裸题）

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define inf 0x3f3f3f3f
#define N 2010
#define M 10010
#define pa pair<int,int>
inline int read(){
int x=0,f=1;char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
while(ch>='0'&&ch<='9') x=x*10+ch-'0',ch=getchar();
return x*f;
}
int n,m,ans=0,fa
;
struct edge{
int x,y,val;
}e[M];
inline bool cmp(edge x,edge y){
return x.val<y.val;
}
inline int find(int x){return x==fa[x]?x:fa[x]=find(fa[x]);}
int main(){
//  freopen("a.in","r",stdin);
n=read();m=read();
for(int i=1;i<=m;++i) e[i].x=read(),e[i].y=read(),e[i].val=read();
sort(e+1,e+m+1,cmp);
for(int i=1;i<=n;++i) fa[i]=i;
for(int i=1;i<=m;++i){

4000
int xx=find(e[i].x),yy=find(e[i].y);
if(xx!=yy){
fa[xx]=yy;ans=e[i].val;
}
}
printf("%d\n",ans);
return 0;
}