POJ1287 最小生成树 水题 ZOJ1372

#include
#include
#include
using namespace std;
#include
int father[51];
struct Road
{
    int x,y,cost;
}road[2500];
int cmp(Road x,Road y)
{
    return x.cost < y.cost;
}
int find(int x)
{
    if(x != father[x])
    return father[x] = find(father[x]);
    return x;
} 
int merge(int x,int y)
{
    int a = find(x);
    int b = find(y);
    if( a != b)
    {
        father[a] = b;
        return 1;
    }
    return 0;
}
int main()
{
    int n,m,i,j,ans;
    while(scanf("%d",&n),n)
    {
        for (i = 0 ;i <= 50;i++)
        father[i] = i;
        memset(road,-1,sizeof(road));
        ans = 0;
        j = 1;
        scanf("%d",&m);
        for (i = 0;i < m;i++)
        scanf("%d%d%d",&road[i].x,&road[i].y,&road[i].cost);
        sort(road,road+m,cmp);
        for( i = 0;i < m;i++)
        {
            if(merge(road[i].x,road[i].y))
            {
                ans +=road[i].cost;
                j++;
            }
            if(j == n)
            break;
        }
        printf("%d\n",ans);
    }
    return 0;
}