Path Sum

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:

    def hasPathSum(self, root: TreeNode, targetSum: int) -> bool:
        # Base case if "after" leaf node
        if not root:
            return False

        # Update target sum to subtract current node's value
        newTargetSum = targetSum - root.val

        # Base case if reached leaf node
        if not root.left and not root.right:
            # Normal case: Return True if path found
            if newTargetSum == 0:
                return True
            # Normal case: Return False if path not found
            return False

        # Return if there is a path in the left subtree or a path in the right subtree
        return self.hasPathSum(root.left, newTargetSum) or self.hasPathSum(root.right, newTargetSum)