参考代码:
class TreeNode:
def __init__(self, val):
self.val = val
self.left = None
self.right = None
class Solution:
def isComplete(self, root):
if root is None:
return True
queue = [root]
index = 0
while index < len(queue):
if queue[index] is not None:
queue.append(queue[index].left)
queue.append(queue[index].right)
index += 1
while queue[-1] is None:
queue.pop()
for q in queue:
if q is None:
return False
return True