hdu1102 Constructing Roads 基础最小生成树

//克鲁斯卡尔（最小生成树）
#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;

const int maxn = 100005;
int n, t;
struct node
{
    int bagin, end, len;
}arr[maxn];
int fa[maxn];

void init()
{
    for (int i = 0; i <= n; i++)
    {
        fa[i] = i;
    }
}

bool cmp(node a, node b)
{
    return a.len<b.len;
}

int find(int x)
{
    if (x != fa[x])
        fa[x] = find(fa[x]);
    return fa[x];
}

int main()
{
    while (cin >> n)
    {
        t = 0;
        for (int i = 1; i <= n; i++)
        {
            for (int j = 1; j <= n; j++)
            {
                int x;
                cin >> x;
                arr[t].bagin = i; arr[t].end = j; arr[t].len = x;
                t++;
            }
        }
        sort(arr, arr + t, cmp);
        init();
        int m;
        cin >> m;
        while (m--)
        {
            int a, b;
            cin >> a >> b;
            int fx, fy;
            fx = find(a); fy = find(b);
            fa[fy] = fx;
        }
        int ans = 0;
        for (int i = 0; i<t; i++)
        {
            int fx, fy;
            fx = find(arr[i].bagin);
            fy = find(arr[i].end);
            if (fx != fy)
            {
                ans += arr[i].len;
                fa[fy] = fx;
            }
        }
        cout << ans << endl;
    }
    return 0;
}