Treegram

How To Play

You're given a set of letters. Place them one at a time into the nodes of a binary tree. Once every letter is placed, the game reads the tree back out four different ways — find at least two that spell different valid words and you've got a solution.

The four traversals

• Breadth-first — level by level, left to right
• Pre-order — recursively: node, then left subtree, then right subtree
• In-order — recursively: left subtree, then node, then right subtree
• Post-order — recursively: left subtree, then right subtree, then node

     1
    / \
   2   3
  /   / \
 4   5   6

• Breadth-first: 1-2-3-4-5-6
• Pre-order: 1-2-4-3-5-6
• In-order: 4-2-1-5-3-6
• Post-order: 4-2-5-6-3

Example

Letters: A D E E L P S

     p
    / \
   l   s
  / \   \
 e   a   e
          \
           d

Pre-order: pleased
In-order: elapsed

Trees with 3 valid words are rarer and worth more. Keep discovering different trees to fill your progress bar for the day!