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LC 0129 [M] Sum Root to Leaf Numbers
Code with Senpai edited this page Sep 21, 2022
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5 revisions
# 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 sumNumbers(self, root: Optional[TreeNode]) -> int:
def preorder(node, pathSum):
if not node: return 0
pathSum = pathSum*10 + node.val
if not node.left and not node.right:
return pathSum
L = preorder(node.left, pathSum) # left path subtree
R = preorder(node.right, pathSum) # right path subtree
return L + R
return preorder(root, 0)
# 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 sumNumbers(self, root: TreeNode) -> int:
return self.helper(root, 0)
def helper(self, node, pathSum):
if node is None:
return 0
pathSum = pathSum*10 + node.val
if node.left is None and node.right is None:
return pathSum
return self.helper(node.left, pathSum) + self.helper(node.right, pathSum)
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