0872-leaf-similar-trees.rb

# frozen_string_literal: true

# 872. Leaf-Similar Trees
# https://leetcode.com/problems/leaf-similar-trees
# Easy

=begin
Consider all the leaves of a binary tree, from left to right order, the values of those leaves form a leaf value sequence.

For example, in the given tree above, the leaf value sequence is (6, 7, 4, 9, 8).

Two binary trees are considered leaf-similar if their leaf value sequence is the same.

Return true if and only if the two given trees with head nodes root1 and root2 are leaf-similar.

Example 1:
Input: root1 = [3,5,1,6,2,9,8,null,null,7,4], root2 = [3,5,1,6,7,4,2,null,null,null,null,null,null,9,8]
Output: true

Example 2:
Input: root1 = [1,2,3], root2 = [1,3,2]
Output: false

Constraints:
The number of nodes in each tree will be in the range [1, 200].
Both of the given trees will have values in the range [0, 200].
=end

# Definition for a binary tree node.
# class TreeNode
#     attr_accessor :val, :left, :right
#     def initialize(val = 0, left = nil, right = nil)
#         @val = val
#         @left = left
#         @right = right
#     end
# end
# @param {TreeNode} root1
# @param {TreeNode} root2
# @return {Boolean}
def leaf_similar(root1, root2)
  leafs(root1) == leafs(root2)
end

def leafs(root)
  return [root.val] if !root.left && !root.right

  result = []

  result += leafs(root.left) if root.left
  result += leafs(root.right) if root.right
  result
end