二叉树问题---判断二叉树是否为平衡二叉树

#判断二叉树是否为平衡二叉树def isBalance(root):    def judgeIsBalance(root, level, res):        if not root:            return level        lH = judgeIsBalance(root.left , level+1, res)        if res[0] == False:            return level        rH = judgeIsBalance(root.right , level+1, res)        if res[0] == False:            return level        if abs(lH - rH) > 1:            res[0] = False        return max(lH, rH)    if not root:        return True    res = [True]    judgeIsBalance(root, 1, res)    return res[0]