Path Sum Python Solution with Tests

lcpy gen -n 112   # by problem number
lcpy gen -s path_sum   # by problem name

Input: root = [5,4,8,11,null,13,4,7,2,null,null,null,1], targetSum = 22
Output: true
Explanation: The root-to-leaf path with the target sum is shown.

Input: root = [1,2,3], targetSum = 5
Output: false
Explanation: There are two root-to-leaf paths in the tree:
(1 --> 2): The sum is 3.
(1 --> 3): The sum is 4.
There is no root-to-leaf path with sum = 5.

Input: root = [], targetSum = 0
Output: false
Explanation: Since the tree is empty, there are no root-to-leaf paths.

from leetcode_py import TreeNode


class Solution:
    # Time: O(n)
    # Space: O(h)
    def has_path_sum(self, root: TreeNode[int] | None, target_sum: int) -> bool:
        if root is None:
            return False
        remaining = target_sum - root.val
        if root.left is None and root.right is None:
            return remaining == 0
        return self.has_path_sum(root.left, remaining) or self.has_path_sum(root.right, remaining)