POJ 1287 Networking (最小生成树)

#include <iostream>
#include <cstdio>
#include <string>
#include <queue>
#include <vector>
#include <map>
#include <algorithm>
#include <cstring>
#include <cctype>
#include <cstdlib>
#include <cmath>
#include <ctime>
using    namespace    std;

const    int    SIZE = 105;
int    N,M;
int    FATHER[SIZE];
int    MAP[SIZE][SIZE];
struct    Node
{
    int    from,to,cost;
}G[SIZE];

void    ini(void);
int    find_father(int);
void    unite(int,int);
bool    same(int,int);
bool    comp(const Node &,const Node &);
int    kruskal(void);
int    main(void)
{
    int    from,to,cost;

    while(~scanf("%d",&N))
    {
        if(!N)
            break;
        scanf("%d",&M);
        ini();
        for(int i = 0;i < M;i ++)
            scanf("%d%d%d",&G[i].from,&G[i].to,&G[i].cost);
        sort(G,G + M,comp);
        printf("%d\n",kruskal());
    }

    return    0;
}

void    ini(void)
{
    fill(&MAP[0][0],&MAP[SIZE - 1][SIZE - 1],-1);
    for(int i = 1;i <= N;i ++)
        FATHER[i] = i;
}

int    find_father(int n)
{
    if(n == FATHER[n])
        return    n;
    return    FATHER[n] = find_father(FATHER[n]);
}

void    unite(int x,int y)
{
    x = find_father(x);
    y = find_father(y);

    if(x == y)
        return    ;
    FATHER[x] = y;
}

bool    same(int x,int y)
{
    return    find_father(x) == find_father(y);
}

int    kruskal(void)
{
    int    ans = 0,count = 0;

    for(int i = 0;i < M;i ++)
        if(!same(G[i].from,G[i].to))
        {
            unite(G[i].from,G[i].to);
            ans += G[i].cost;
            count ++;

            if(count == N - 1)
                break;
        }
    return    ans;
}

bool    comp(const Node & a,const Node & b)
{
    return    a.cost < b.cost;
}