poj1251--Kruskal

标签：algorithm   poj   kruskal   

/*
* poj1251-- Kruskal
* date 2014/7/15
* state AC
*/

#include <iostream>
#include <algorithm>
#include <fstream>
#include <cstdio>
#include <cstring>

using namespace std;

int const MAXN=30+100;
int u[MAXN];
int v[MAXN];
int w[MAXN+50];

int p[MAXN];
int r[MAXN];

int cmp(const int i,const int j)
{
    return w[i]<w[j];
}

int unionFindSet(int x)
{
    return p[x]==x?x:p[x]=unionFindSet(p[x]);
}

int Kruskal(int n,int m)
{
    int ans=0;

    //memset(p,0,sizeof(p));
    //memset(r,0,sizeof(r));

    for(int i=0;i<n;i++)
        p[i]=i;
    for(int i=0;i<m;i++)
        r[i]=i;

    //mem
    sort(r,r+m,cmp);
    for(int i=0;i<m;i++)
    {
        int e=r[i];
        int x=unionFindSet(u[e]);
        int y=unionFindSet(v[e]);
        if(x!=y)
        {
            ans+=w[e];
            p[x]=y;
        }
    }
    return ans;
}
int main()
{
    //cout << "Hello world!" << endl;
    //freopen("input.txt","r",stdin);
    char a[2],b[2];
    int c;
    int m;
    int n;
    int edgeNum;
    while(scanf("%d",&n))
    {
        if(n==0)break;

        memset(u,0,sizeof(u));
        memset(v,0,sizeof(v));
        memset(w,0,sizeof(w));

        edgeNum=0;
        for(int i=0;i<n-1;i++)
        {
            scanf("%s%d",a,&m);
            for(int j=0;j<m;j++)
            {
                scanf("%s%d",b,&c);
                u[edgeNum]=a[0]-'A';
                v[edgeNum]=b[0]-'A';
                w[edgeNum]=c;
                edgeNum++;
            }
        }
        //
        /*cout<<"edgeNumber: "<<edgeNum<<endl;
        for(int k=0;k<edgeNum;k++)
            cout<<u[k]<<" "<<v[k]<<" "<<w[k]<<"    ";
        cout<<"---"<<endl;
        */
        cout<<Kruskal(n,edgeNum)<<endl;
    }
    return 0;
}

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poj1251--Kruskal

标签：algorithm   poj   kruskal   

原文地址：http://blog.csdn.net/greenapple_shan/article/details/37814725