评测地址：https://www.luogu.com.cn/record/89111811

代码：

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 1;
const int M = 1e2 + 1;
int n, ans;
vector<vector<int>> v[N];
int fa[M], siz[M];

int find_root (int a) {
    if (fa[a] != a) {
        return find_root(fa[a]);
    }
    return a;
}

void _union (int a, int b) {
    int ra = find_root(a);
    int rb = find_root(b);
    if (ra == rb) {
        return;
    }
    if (siz[ra] > siz[rb]) {
        swap(ra, rb);
    }
    fa[ra] = rb;
    siz[rb] += siz[ra];
}

int main () {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        fa[i] = i;
        siz[i] = 1;
    }
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            int x;
            cin >> x;
            if (i >= j) {
                continue;
            }
            vector<int> pair = {i, j};
            v[x].push_back(pair);
        }
    }
    for (int i = 0; i <= N; i++) {
        for (int j = 0; j < v[i].size(); j++) {
            const int a = v[i][j][0];
            const int b = v[i][j][1];
            const int ra = find_root(a);
            const int rb = find_root(b);
            if (ra == rb) {
                continue;
            }
            _union(ra, rb);
            ans += i;
            if (siz[ra] == n || siz[rb] == n) {
                cout << ans << endl;
            }
        }
    }
    return 0;
}

其他的并查集题目也是这样做的，没出什么问题