HDoj-1863-畅通工程-并查集

标签：des   io   os   java   for   sp   数据   on   amp   

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#include <stdio.h> 
#include<string.h>
#include <algorithm>
using namespace std;
struct Road
{
    int c1, c2, cost;
};
Road road[110];

bool cmp(Road a,Road b)
{
    return a.cost<b.cost;
}
int city[110];

int find(int a)
{
    int r=a;
    while(city[r]!=r)
       r=city[r];
    return r;
}
bool merge(int x, int y)
{
    int fx,fy;
     fx = find(x);
     fy = find(y);
    if(fx == fy)   return 0;
    else if(fx < fy)
           city[fy] = fx;
    else
           city[fx] = fy;
return 1;
} 

int main()
{
    int n, m;                         
    while(scanf("%d %d", &m, &n) && m)
    {
        int i;
        for(i=1;i<=n;i++) 
        {
            city[i]=i;
        }
        for(int i=0; i<m; ++i)
            scanf("%d %d %d", &road[i].c1, &road[i].c2, &road[i].cost);
        sort(road, road+m,cmp);
        int sum = 0, count = 0;
        for(int i=0; i<m; i++)
        {
            if(merge(road[i].c1, road[i].c2))
            {
                count ++;
                sum += road[i].cost;
            }
            if(count == n-1)
                break;
        }
        if(count == n-1)
            printf("%d\n", sum);
        else
            printf("?\n");
    }
    return 0;
}

HDoj-1863-畅通工程-并查集

标签：des   io   os   java   for   sp   数据   on   amp   

原文地址：http://blog.csdn.net/holyang_1013197377/article/details/40047729