Even Odd Tree Python Solution with Tests

lcpy gen -n 1609   # by problem number
lcpy gen -s even_odd_tree   # by problem name

Input: root = [1,10,4,3,null,7,9,12,8,6,null,null,2]
Output: true
Explanation: The node values on each level are:
Level 0: [1]
Level 1: [10,4]
Level 2: [3,7,9]
Level 3: [12,8,6,2]
Since levels 0 and 2 are all odd and increasing and levels 1 and 3 are all even and decreasing, the tree is Even-Odd.

Input: root = [5,4,2,3,3,7]
Output: false
Explanation: The node values on each level are:
Level 0: [5]
Level 1: [4,2]
Level 2: [3,3,7]
Node values in level 2 must be in strictly increasing order, so the tree is not Even-Odd.

Input: root = [5,9,1,3,5,7]
Output: false
Explanation: Node values in the level 1 should be even integers.

from leetcode_py import TreeNode


class Solution:
    # Time: O(n)
    # Space: O(w) where w is the max level width
    def is_even_odd_tree(self, root: TreeNode[int] | None) -> bool:
        if root is None:
            return False
        level = [root]
        depth = 0
        while level:
            prev = None
            for node in level:
                val = node.val
                if depth % 2 == 0:
                    if val % 2 == 0:
                        return False
                    if prev is not None and val <= prev:
                        return False
                else:
                    if val % 2 == 1:
                        return False
                    if prev is not None and val >= prev:
                        return False
                prev = val
            level = [child for node in level for child in (node.left, node.right) if child]
            depth += 1
        return True