513-Find Bottom Left Tree Value

1. Find Bottom Left Tree Value Solved Medium Topics Companies Given the root of a binary tree, return the leftmost value in the last row of the tree.

Example 1:

Input: root = [2,1,3] Output: 1 Example 2:

Input: root = [1,2,3,4,null,5,6,null,null,7] Output: 7

My solution：

# 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
from collections import deque
class Solution(object):
    def findBottomLeftValue(self, root):
        """
        :type root: Optional[TreeNode]
        :rtype: int
        """
        
        queue = deque()
        queue.append(root)
        leftMostTmp = None
        while queue:
            length = len(queue)
            leftMostTmp = queue.popleft()
            if leftMostTmp.left:
                    queue.append(leftMostTmp.left)
            if leftMostTmp.right:
                queue.append(leftMostTmp.right)

            for i in range(1,length):
                tmp = queue.popleft()
                if tmp.left:
                    queue.append(tmp.left)
                if tmp.right:
                    queue.append(tmp.right)

        return leftMostTmp.val