Disjoint Set implementation

disjointset.cpp

template<typename T>
class disjointset
{
  public:
  disjointset(int n) {
    size = n;
    arr.reserve(n);
    rank.reserve(n);
    makeSet();
    setcount = n;
  }
  void makeSet() {
    for(size_t i=0;i<size;i++){ 
      arr[i] = i;
      rank[i] = 1;
    }      
  }

  T find(T a) {
    if (arr[a]!=a)
      arr[a] = find(arr[a]);
    return arr[a];
  }

  void unite(T a,T b) {
    T arep = find(a);
    T brep = find(b);

    if (arep == brep) {
      return;
    } else if (rank[a] < rank[b]) {
      arr[brep] = arep;
      rank[arep] += rank[brep];
    } else if (rank[a] > rank[b]){
      arr[arep] = brep;
      rank[brep] += rank[arep];
    } else {
      arr[arep] = brep;
      rank[brep] += rank[arep];
    }
  }

  T getSetSize(T a){
      return rank[a];
  }

  private:
  int size;
  int setcount;
  vector<T> arr;
  vector<T> rank;
};