zoj3204 Connect them 最小生成树

题目链接：http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=3367

题目就是简单的最小生成树的模板的应用，不过最小生成树可能不唯一，答案要求输出字典序最小

代码：

#include<cstdlib>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
#define maxn 110
int n,tol;
int cnt;
class node
{
    public:
    int from;
    int to;
    int w;
};
node edge[maxn*maxn];
node ans[maxn*maxn];
int parent[maxn*maxn];
void addedge(int u,int v,int w)
{
    edge[tol].from=u;
    edge[tol].to=v;
    edge[tol].w=w;
    tol++;
}
void UFset()
{
    for(int i=0;i<maxn*maxn;i++)
       parent[i]=-1;
}
int Find( int x)
{
   int s;
   for(s=x;parent[s]>=0; s=parent[s]);
   while(s!=x)
   {
      int tmp=parent[x];
      parent[x]=s;
      x=tmp;
   }
   return s;
}
void Union(int R1, int R2)
{
    int root1=Find(R1);
    int root2=Find(R2);

    int tmp=parent[root1]+parent[root2];

    if(parent[root1]> parent[root2])
     {
         parent[root1]=root2;
         parent[root2]=tmp;
     }
     else
     {
         parent[root2]=root1;
         parent[root1]=tmp;
     }
}
bool cmp1( node a, node b)
{
    if(a.w!=b.w)return a.w<b.w;
       else if(a.from!=b.from)return a.from<b.from;
          else return a.to<b.to; 
}
bool cmp2(node a, node b)
{
  if(a.from!=b.from)return a.from<b.from;
     else return a.to<b.to; 
}
void Kruskal()
{
   int num=0;
   int u,v;
   UFset();
   cnt=0;

   for(int i=0;i<tol;i++)
    {
       u=edge[i].from;
       v=edge[i].to;
       if(Find(u) != Find(v))
       {
           ans[cnt++]=edge[i];
           Union(u,v);
       }
       
    }
}
int main()
{
     int t;
     scanf("%d",&t);
     while(t--)
     {
        scanf("%d",&n);
        tol=0;
        int  weight;
        for(int i=1;i<=n;i++)
          for(int j=1;j<=n;j++)
           {
                scanf("%d",&weight);
                if(j<=i) continue;
                if(weight==0 ) continue;
                addedge(i,j,weight);
           }
         sort(edge,edge+tol,cmp1);
           
         Kruskal();

         if(cnt!=n-1)
              cout<<"-1"<<endl;
           else
              {
                  sort(ans,ans+cnt,cmp2);
                  cout<<ans[0].from<<" "<<ans[0].to;
                  for(int i=1;i<cnt;i++)
                      cout<<" "<<ans[i].from<<" "<<ans[i].to;
                      cout<<endl;
              }
     }
     return 0;
}