题解 | #判断是不是完全二叉树#

写的很长很臭的 BFS

# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param root TreeNode类 
# @return bool布尔型
#
class Solution:
    def isCompleteTree(self , root: TreeNode) -> bool:
        # write code here
        """层序遍历"""
        q = []
        q.append(root)
        cnt = 1
        while q:
            tmp = q 
            q = []
            flag = True
            for i, node in enumerate(tmp):
                
                for x in [node.left, node.right]:
                    if x and flag:
                        q.append(x)
                    elif x and not flag:
                        
                        return False
                    else:
                        flag = False
            if len(q) != 2 ** cnt:
                break
            cnt += 1
#         print(q)
        for node in q:
            if node.left or node.right:
                return False
        
        return True