To_Heart—题解——NOIP2010 关押罪犯

思路：

，

#include<bits/stdc++.h>
using namespace std;

int pre[200005];

void FuChuZhi(int n){
	for(int i=1;i<=n;i++)
		pre[i]=i;
}

int Find(int x){
	if(pre[x]!=x){
		pre[x]=Find(pre[x]);
	}
	return pre[x];
} 

void Join(int x,int y){
	int fx=Find(x),fy=Find(y);
	if(fx!=fy){
		pre[fx]=fy;
	}
}

struct zz{
	int a,b,c;
} dp[10000005];

bool cmp(zz x,zz y){
	return x.c>y.c;
}

int main(){
	int n,m;
	cin>>n>>m;
	FuChuZhi(n*2);
	for(int i=1;i<=m;++i){
		scanf("%d%d%d",&dp[i].a,&dp[i].b,&dp[i].c);
	}
	int sum=0;
	sort(dp+1,dp+m+1,cmp);
	for(int i=1;i<=m;++i){
		int fx=Find(dp[i].a),fy=Find(dp[i].b);
		if(fx==fy){
			printf("%d",dp[i].c);
			return 0;
		}
		Join(fx,dp[i].b+n);
		Join(fy,dp[i].a+n);
	}
	printf("0");
}