POj 1797 Heavy Transportation

#include<stdio.h>
#include<algorithm>
using namespace std;

const int MAXN=1005;
const int INF=0x7fffffff;

int father[MAXN];
int rank[MAXN];
int ans,n,m;

struct Edge
{
    int u,v;
    int w;
}edge[100000];//这里数组开小了re，题目并没有说m的大小，仅仅说了n的大小

bool cmp(Edge a,Edge b)
{
    return a.w>b.w;//这里是关键不是从小到大了
}

void Make_set(int n)
{
    for (int i=0;i<=n;i++)
    {
        father[i]=i;
        rank[i]=0;
    }
}

int Find_set(int x)
{
    int r=x;
    while(r!=father[r])
    {
        r=father[r];
    }
    if(r!=x) father[x]=r;
    return r;
}

void Union(int x,int y)
{
    if(x==y) return ;
    if(rank[x]>rank[y])
    {
        father[y]=x;
    }
    else
    {
        if(rank[x]==rank[y])
        {
            rank[y]++;
        }
        father[x]=y;
    }
}

void Kruskal(int cas)
{
    sort(edge,edge+cas,cmp);
    ans=INF;
    for (int i=0;i<cas;i++)
    {
        int x=Find_set(edge[i].u);
        int y=Find_set(edge[i].v);
        if(x!=y) Union(x,y);
        if(ans>edge[i].w)  ans=edge[i].w;
        if(Find_set(1)==Find_set(n)) break;
    }
}

int main()
{
    int T,i;
    int tes=1;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d%d",&n,&m);
        for (i=0;i<m;i++)
        {
            scanf("%d%d%d",&edge[i].u,&edge[i].v,&edge[i].w);
        }
        Make_set(n);
        Kruskal(m);
        printf("Scenario #%d:\n",tes++);
        printf("%d\n\n",ans);//后面还有一个空白空格，没看见
    }
    return 0;
    
}