Problem Statement
- Leetcode Sum of Left Leaves
Given the
root
of a binary tree, return the sum of all left leaves.
A leaf is a node with no children. A left leaf is a leaf that is the left child of another node.
Input: root = [3,9,20,null,null,15,7] Output: 24 Explanation: There are two left leaves in the binary tree, with values 9 and 15 respectively.
My Solution
# 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 recursiveLeftSum(self, node: Optional[TreeNode], sum: int, leftChild: bool) -> int:
# Base case
if (not node):
return 0
if (node.left == None and node.right == None and leftChild == True):
# This is a leaf node and it is a left child, so add to sum
return node.val
if (node.left == None and node.right == None and leftChild == False):
return 0
# Recursively call left and right branches and return sum
return sum + self.recursiveLeftSum(node.left, sum, True) + self.recursiveLeftSum(node.right, sum, False)
def sumOfLeftLeaves(self, root: Optional[TreeNode]) -> int:
recursiveLeftSum