0112-path-sum.py

class Solution:
    def hasPathSum(self, root, sum):
        if not root:
            return False
        de = [
            (root, sum - root.val),
        ]
        while de:
            node, curr_sum = de.pop()
            if not node.left and not node.right and curr_sum == 0:
                return True
            if node.right:
                de.append((node.right, curr_sum - node.right.val))
            if node.left:
                de.append((node.left, curr_sum - node.left.val))
        return False