Disjoint Set Union.cpp

int parent[N], size[N];

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

void make(int v) {
    parent[v] = v;
    size[v] = 1;
}

void unite(int a, int b) {
    a = find(a);
    b = find(b);
    if (a != b) {
        if (size[a] < size[b])
            swap(a, b);
        parent[b] = a;
        size[a] += size[b];
    }
}


class dsu {
 public:
  vector<int> p;
  int n;
 
  dsu(int _n) : n(_n) {
    p.resize(n);
    iota(p.begin(), p.end(), 0);
  }
 
  inline int get(int x) {
    return (x == p[x] ? x : (p[x] = get(p[x])));
  }
 
  inline bool unite(int x, int y) {
    x = get(x);
    y = get(y);
    if (x != y) {
      p[x] = y;
      return true;
    }
    return false;
  }
};