message: Update all-possible-full-binary-trees.py
diff: -# Time: O(n * 4^n / n^(3/2)) ~= Catalan numbers
  -# Space: O(n * 4^n / n^(3/2)) ~= Catalan numbers
  +# Time: O(n * 4^n / n^(3/2)) ~= sum of Catalan numbers from 1 .. N
  +# Space: O(n * 4^n / n^(3/2)) ~= sum of Catalan numbers from 1 .. N
  # A full binary tree is a binary tree where each node has exactly 0 or 2 children.
  #
  