public int[] molecularSizeDistrb(){
    
    int maxSize=0;
    
    for (int i=0; i<bucket.size(); i++){
      maxSize = (bucket.get(i).getSize() > maxSize)? bucket.get(i).getSize() : maxSize;
    }
    
    int[] sizeDistrb = new int[maxSize+1];
  
    for (int i=1; i<bucket.size(); i++){
    
      sizeDistrb[bucket.get(i).getSize()] += bucket.get(i).getSize();
      
    }
    
    return sizeDistrb;
    
  }