喂AI？？

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

vector<int> parent;
vector<int> key_pos;

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

void unite(int x, int y) {
int fx = find(x);
int fy = find(y);
if (fx != fy) {
parent[fy] = fx;
}
}

int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);

int n, m, p;
cin >> n >> m >> p;

parent.resize(n + 2);
key_pos.resize(n + 2, 0);

for (int i = 1; i <= n; i++) {
    parent[i] = i;
}

for (int i = 0; i < m; i++) {
    int x, y;
    cin >> x >> y;
    key_pos[x] = y;
}

// 预处理连通性
for (int i = 1; i < n; i++) {
    if (key_pos[i] == 0) {
        unite(i, i + 1);
    } else {
        // 检查是否能拿到钥匙
        if (find(key_pos[i]) == find(i)) {
            unite(i, i + 1);
        }
    }
}

// 处理查询
while (p--) {
    int s, t;
    cin >> s >> t;
    if (s == t) {
        cout << "YES\n";
        continue;
    }
    if (s < t) {
        bool reachable = true;
        int current = s;
        while (current < t) {
            if (find(current) == find(current + 1)) {
                current++;
            } else if (key_pos[current] != 0 && find(key_pos[current]) == find(current)) {
                unite(current, current + 1);
                current++;
            } else {
                reachable = false;
                break;
            }
        }
        cout << (reachable ? "YES" : "NO") << "\n";
    } else {
        bool reachable = true;
        int current = s;
        while (current > t) {
            if (find(current) == find(current - 1)) {
                current--;
            } else if (key_pos[current - 1] != 0 && find(key_pos[current - 1]) == find(current)) {
                unite(current, current - 1);
                current--;
            } else {
                reachable = false;
                break;
            }
        }
        cout << (reachable ? "YES" : "NO") << "\n";
    }
}

return 0;

}