数据结构实验之图论九：最小生成树 （SDUT 2144）

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
struct node
{
    int s, e;
    int w;
}s[100005];
int c[105];
bool cmp(struct node a, struct node b)
{
    return a.w < b.w;
}
int fin(int x)
{
    int r = x;
    while(r != c[r]) r = c[r];
    int i = x, j;
    while(c[i] != r)
    {
        j = c[i];
        c[i] =r;
        i = j;
    }
    return r;
}
int merge(int x, int y)
{
    if(fin(x) != fin(y))
    {
        c[fin(x)] = fin(y);
        return 1;
    }
    return 0;
}
int main()
{

    int n,m,a,b,w;
    while(scanf("%d%d",&n,&m) != EOF)
    {
        for(int i = 0; i < m; i ++)
        {
            scanf("%d%d%d",&a,&b,&w);
            s[i].s = a;
            s[i].e = b;
            s[i].w = w;
        }
        sort(s,s+m,cmp);
        int ans = 0, cnt = 0;
        for(int i = 0; i <= n; i ++)c[i] = i;
        for(int i = 0; i < m; i ++)
        {
            if(merge(s[i].s,s[i].e)== 1)
            {
                ans += s[i].w;
                cnt ++;
            }
            if(cnt == n - 1) break;
        }
        printf("%d\n",ans);
    }
    return 0;
}