Network POJ 1861 ZOJ 1542 Kruskal算法 提问方式有点变化而已

和ZOJ 1203解法一样，不赘述，我都直接复制的代码修改了一下

贴代码：

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#define MAXN  1020
#define MAXM 15020
using namespace std;
int n,m;  //n为顶点个数，m为边数
struct ArcNode
{
    int u,v;  //一条边的起点和终点
    int w;  //边的权值
    bool operator <(const ArcNode & other) const
    {
        if(w < other.w) return true;
        else return false;
    };
} edge[MAXM];  //存边
int parent[MAXN];  //用于并查集
int l[MAXN];
int Find(int x)
{
    int s;
    for(s = x; parent[s] >= 0; s = parent[s]);
    while(s != x)
    {
        int temp = parent[x];
        parent[x] = s;
        x = temp;
    }
    return s;
}
void Union(int x,int y)
{
    int r1 = Find(x);
    int r2 = Find(y);
    int temp = parent[r1] +parent[r2];//两根结点所带结点的总数
    if(parent[r1] > parent[r2])
    {
        parent[r1] = r2;
        parent[r2] = temp;
    }
    else
    {
        parent[r2] = r1;
        parent[r1] = temp;
    }
}
void Kruskal()
{
    int i;
    for(i=1; i <= n; i++)
        parent[i] = -1;
    int num =0;
    sort(edge,edge+m);
    for(i=0; i<m; i++)
    {
        int u = edge[i].u;
        int v = edge[i].v;
        if(Find(u) != Find(v))
        {
            Union(u,v);
            l[num++] = i;
        }
        if(num >= n-1) break;
    }
}
int main()
{
//    freopen("in.cpp","r",stdin);
    int i;
    while(~scanf("%d%d",&n,&m))
    {
        for(i=0; i<m; i++)
        {
            scanf("%d%d%d",&edge[i].u,&edge[i].v,&edge[i].w);
        }
        Kruskal();
        printf("%d\n%d\n",edge[l[n-2]].w,n-1);
        for(i =0; i<n-1; i++)
            printf("%d %d\n",edge[l[i]].u,edge[l[i]].v);
    }
    return 0;
}