setunion

int findroot(int x, vector<int> &parent) {
    while (x != parent[x]) x = parent[x];
    return x;
}

void connect(int x, int y, vector<int> &parent) {
    parent[findroot(y,parent)] = findroot(x, parent);
}

bool isConnected(int x, int y, vector<int> &parent) {
    return findroot(x, parent) == findroot(y, parent);
}