CCF CSP 地铁修建

#include <cstdio>
#include <algorithm>
#include <iostream>
#include <queue>
using namespace std;

const int maxn(1e5 + 10);
int father[maxn];
struct edge{
int src, dest;
int dis;
edge(int src, int dest, int dis){
this->src = src;
this->dest = dest;
this->dis = dis;
}
edge(){}
};
inline bool operator < (const edge &first, const edge &second){
return (first.dis > second.dis);
}
int n, m;
void init();
int find(int);
int main()
{
while(scanf("%d %d",&n, &m) != EOF) {
init();
priority_queue <edge> pq;
int rest = n - 1;
int src, dest, dis;
int ans = 0;
for(int i = 0; i < m; i++){
scanf("%d %d %d",&src,&dest,&dis);
pq.push(edge(src,dest,dis));
}
while(rest && !pq.empty() && find(1) != find(n)){
edge cur = pq.top();
pq.pop();
if(find(cur.src) != find(cur.dest)){
rest--;
father[find(cur.src)] = find(cur.dest);
ans = max(ans,cur.dis);
}
}
printf("%d\n",ans);
}
return 0;
}
void init(){
for(int i = 1; i <= n; i++){
father[i] = i;
}
}
int find(int index){
if(father[index] == index){
return index;
}
return (father[index] = find(father[index]));
}