[Leet Code] Find Bottom Left Tree Value

Input: root = [2,1,3]
Output: 1
Input: root = [1,2,3,4,null,5,6,null,null,7]
Output: 7
# Definition for a binary tree node.
# class TreeNode(object):
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution(object):
def findBottomLeftValue(self, root):
"""
:type root: TreeNode
:rtype: int
"""
if root:
elements = [[root.val]]
stack = [root]
self.helper(stack, elements)
length = len(elements) - 1
for i in range(len(elements)):
if i == length:
return elements[i][0]

def helper(self, stack, elements):
while len(stack) > 0:
values = []
length = len(stack)
for i in range(length):
node = stack.pop(0)
if node.left:
stack.append(node.left)
values.append(node.left.val)
if node.right:
stack.append(node.right)
values.append(node.right.val)
if values != []:
elements.append(values)

--

--

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Matthew Boyd

Matthew Boyd

Learning, and posting my findings!