/*==============================
8 name:bucket sort
--------------------------------
time complexity:
average
O(n+nlogn-nlogm)
--------------------------------
space complexity:
O(n)
--------------------------------
stability:
unstable
==============================*/
//suppose: 0<data[i]<100
//we should design the project function based on the data distribution
void bucket_sort(std::vector<int> &a)
{
  std::vector<std::vector<int>> bucket;
  bucket.resize(10);
  std::vector<int>::iterator it=a.begin();
  while(it!=a.end())
  {
    int idx=*it/10;
    bucket[idx].push_back(*it);
    it++;
  }
  std::vector<std::vector<int>>::iterator it1=bucket.begin();
  while(it1!=bucket.end())
  {
    simple_sort(*it1);
    it1++;
  }
  it=a.begin();
  it1=bucket.begin();
  while(it!=a.end() && it1!=bucket.end())
  {
    std::vector<int>::iterator tmp_it=(*it1).begin();
    while(tmp_it!=(*it1).end())
    {
      *it=*tmp_it;
      tmp_it++;
      it++;
    }
    it1++;
  }
}