Solution.cpp

class UnionFind {
public:
    UnionFind(int n) {
        p = vector<int>(n);
        size = vector<int>(n, 1);
        iota(p.begin(), p.end(), 0);
    }

    bool unite(int a, int b) {
        int pa = find(a), pb = find(b);
        if (pa == pb) {
            return false;
        }
        if (size[pa] > size[pb]) {
            p[pb] = pa;
            size[pa] += size[pb];
        } else {
            p[pa] = pb;
            size[pb] += size[pa];
        }
        return true;
    }

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

private:
    vector<int> p, size;
};

class Solution {
public:
    vector<bool> areConnected(int n, int threshold, vector<vector<int>>& queries) {
        UnionFind uf(n + 1);
        for (int a = threshold + 1; a <= n; ++a) {
            for (int b = a + a; b <= n; b += a) {
                uf.unite(a, b);
            }
        }
        vector<bool> ans;
        for (auto& q : queries) {
            ans.push_back(uf.find(q[0]) == uf.find(q[1]));
        }
        return ans;
    }
};