Parallel search DSU

class dsu {
    
 public :
  vector<int> f;
  int n;
  dsu(int _n) : n(_n) {
     
    f.resize(n);
    iota(f.begin(), f.end(), 0); 
  }
  inline int found(int x) {
    
    return (x == f[x] ? x : f[x] = found(f[x]));
  }
  inline bool merged(int x, int y) {
    
  	int fx = found(x), fy = found(y);
    if (fx != fy) {
    
      f[fx] = fy;
      return 1;
    }
    return 0;
  }
};