并查集 - 亲戚

#include<iostream>
#include<vector>
using namespace std;

vector<int> fa{ -1 };
int find(int i) {
    if (fa[i] != i) fa[i] = find(fa[i]);
    return fa[i];
}

void merge(int i, int j) {
    fa[find(i)] = find(j);
}

int main() {
    int n, m, p;
    cin >> n >> m >> p;

    for (int i = 1; i <= n; i++) fa.push_back(i);
    for (int i = 0, a, b; i < m; i++) {
        cin >> a >> b;
        merge(a, b);
    }
    string res;
    for (int i = 0, a, b; i < p; i++) {
        cin >> a >> b;
        res += (find(a) == find(b) ? "Yes\n" : "No\n");
    }
    cout << res;
    return 0;
}