Poj 1258 Agri-Net

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
using namespace std;



struct MAP {
    int x;
    int y;
    int cost;
};


MAP m[10001];

void quick_sort(int head, int tail) {
    if (head > tail) {
        return;
    }
    int temp = m[head].cost;
    int i = head;
    int j = tail;
    while (i != j) {
        while (m[j].cost >= temp && i < j) {
            j--;
        }
        while (m[i].cost <= temp && i < j) {
            i++;
        }
        if (i < j) {
            MAP t = m[j];
            m[j] = m[i];
            m[i] = t;
        }
    }
    MAP t = m[head];
    m[head] = m[i];
    m[i] = t;
    quick_sort(head, i - 1);
    quick_sort(i + 1, tail);
}

int f[101];

void init(int n) {
    for (int i = 1; i <= n; i++) {
        f[i] = i;
    }
}


int find(int n) {
    if (n == f[n]) {
        return n;
    }
    int t = find(f[n]);
    f[n] = t;
    return t;
}


void link(int a, int b) {
    int x = find(a);
    int y = find(b);
    if (x != y) {
        f[x] = f[y];
    }
}

bool search(int a, int b) {
    int x = find(a);
    int y = find(b);
    if (x != y) {
        return false;
    }
    return true;
}


int main()
{
    int n;

    while (cin >> n) {
        int a[101][101] = { 0 };
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= n; j++) {
                cin >> a[i][j];
            }
        }
        int t = 0;
        for (int i = 1; i <= n; i++) {
            for (int j = i + 1; j <= n; j++) {
                m[t].x = i;
                m[t].y = j;
                m[t].cost = a[i][j];
                t++;
            }
        }
        quick_sort(0, t - 1);
        init(n);
        int sum = 0;
        for (int i = 0; i < t; i++) {
            if (search(m[i].x, m[i].y) == false) {
                sum += m[i].cost;
                link(m[i].x, m[i].y);
            }
        }
        cout << sum << endl;
    }



    return 0;
}