【最小生成树】BZOJ1682[Usaco2005 Mar]-Out of Hay 干草危机

...最小生成树裸题，9月最后一天刷水刷水。

 #include<iostream>
 #include<cstdio>
 #include<algorithm>
 using namespace std;
 const int MAXM=+;
 const int MAXN=+;
 struct Rec
 {
     int ori,des,len;
     bool operator < (const Rec &x) const
     {
         return len<x.len;
     }
 }edge[MAXM];
 int par[MAXN],height[MAXN];
 int n,m;
 int ans;

 void initset()
 {
     for (int i=;i<=n;i++)
     {
         par[i]=i;
         height[i]=;
     }
 }

 int find(int x)
 {
     int r=x,temp;
     while (par[r]!=r) r=par[r];
     while (x!=r)
     {
         temp=par[x];
         par[x]=r;
         x=temp;
     }
     return (r);
 }

 void unionset(int fa,int fb)
 {
     if (height[fa]>=height[fb])
     {
         par[fb]=fa;
         if (height[fa]==height[fb]) height[fa]++;
     }
     else
         par[fa]=fb;
 }

 void init()
 {
     scanf("%d%d",&n,&m);
     for (int i=;i<m;i++)
     {
         int u,v,w;
         scanf("%d%d%d",&u,&v,&w);
         edge[i].ori=u;
         edge[i].des=v;
         edge[i].len=w;
     }
 }

 void solve()
 {
     sort(edge,edge+m);
     initset();
     ans=;
     for (int i=;i<m;i++)
     {
         int fa=find(edge[i].ori);
         int fb=find(edge[i].des);
         if (fa!=fb)
         {
             unionset(fa,fb);
             ans=max(ans,edge[i].len);
         }
     }
     printf("%d",ans);
 }

 int main()
 {
     init();
     solve();
     return ;
 }