POJ1287 最小生成树 水题 ZOJ1372

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