old_contents: LowestCommonAncestorOfBSTree.js
  
new_contents: // Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST.
  
  // According to the definition of LCA on Wikipedia:
  // “The lowest common ancestor is defined between two nodes v and w as the lowest node in T
  // that has both v and w as descendants (where we allow a node to be a descendant of itself).”
  
  //         _______6______
  //        /              \
  //     ___2__          ___8__
  //    /      \        /      \
  //    0      _4       7       9
  //          /  \
  //          3   5
  // For example, the lowest common ancestor (LCA) of nodes 2 and 8 is 6.
  // Another example is LCA of nodes 2 and 4 is 2, since a node can be a descendant of itself according to the LCA definition.
  
subject: add desc