Solution.cpp

class Solution {
public:
    vector<bool> friendRequests(int n, vector<vector<int>>& restrictions, vector<vector<int>>& requests) {
        vector<int> p(n);
        iota(p.begin(), p.end(), 0);
        function<int(int)> find = [&](int x) {
            if (p[x] != x) {
                p[x] = find(p[x]);
            }
            return p[x];
        };
        vector<bool> ans;
        for (auto& req : requests) {
            int u = req[0], v = req[1];
            int pu = find(u), pv = find(v);
            if (pu == pv) {
                ans.push_back(true);
            } else {
                bool ok = true;
                for (auto& r : restrictions) {
                    int px = find(r[0]), py = find(r[1]);
                    if ((pu == px && pv == py) || (pu == py && pv == px)) {
                        ok = false;
                        break;
                    }
                }
                ans.push_back(ok);
                if (ok) {
                    p[pu] = pv;
                }
            }
        }
        return ans;
    }
};