0662-maximum-width-of-binary-tree.py

# 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 widthOfBinaryTree(self, root: Optional[TreeNode]) -> int:
        qu = [(root, 0, 0)]
        
        cur_depth = left = ans = 0
        for node, depth, pos in qu:
            if node:
                qu.append((node.left, depth+1, pos*2))
                qu.append((node.right, depth+1, pos*2 + 1))
                if cur_depth != depth:
                    cur_depth = depth
                    left = pos
                ans = max(pos - left + 1, ans)

        return ans