ZOJ1542 POJ1861

题意：给你N个点M条边，求最小生成树，并且输出最小生成树里最大的那条边，并且输出路径 

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>
using namespace std;

#define N 1005
#define M 15005
int father[N],rank[N],n,m,sum,MAX,num;
int NUM[N];
struct Edge
{
    int u;
    int v;
    int w;
}edge[M];

bool cmp(Edge a,Edge b)
{
    return a.w < b.w ;
}

void Init()
{
    for(int i=0; i<=n; i++)
    {
        father[i] = i;
        rank[i] = 1;
    }
}

int find(int x)
{
    if(father[x] != x)
    {
        father[x] = find(father[x]);
    }
    return father[x] ;
}

void merge(int x,int y)
{
    int xf = find(x);
    int yf = find(y);
    if(rank[xf] > rank[yf])
    {
        rank[xf] += rank[yf];
        father[yf] = xf;
    }
    else
    {
        rank[yf] += rank[xf];
        father[xf] = yf;
    }
}

void Kruskal()
{
    num = 0; 
    MAX=0;
    for(int i=0; i<m; i++)
    {
        int u = edge[i].u;
        int v = edge[i].v;
        if(find(u) != find(v))
        {
            NUM[num] = i;
            num++ ;
            sum += edge[i].w;
            MAX = max(MAX,edge[i].w);
            merge(u,v);
        }
        if(num == n-1) break;
    }
}

int main()
{
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        Init();
        for(int i=0; i<m; i++)
        {
            scanf("%d%d%d",&edge[i].u,&edge[i].v,&edge[i].w);
        }
        sort(edge,edge+m,cmp);
        sum = 0;
        Kruskal();
        printf("%d\n",MAX);
        printf("%d\n",num);
        for(int i=0; i<num; i++)
        {
            printf("%d %d\n",edge[NUM[i]].u,edge[NUM[i]].v);
        }
    }
    return 0;
}