Leetcode: Symmetric Tree @Python

Iterative solution:

# Iterative Solution
# Definition for a  binary tree node
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    # @param root, a tree node
    # @return a boolean
    def isSymmetric(self, root):
        if root==None:
            return True
        else:
            Ninlvl=[root.left, root.right]
        while Ninlvl!=[None]*len(Ninlvl):
            n=len(Ninlvl)
            if n%2!=0:
                return False
            for i in range(n):
                if Ninlvl[i]==None and Ninlvl[n-i-1]!=None:
                    return False
            ndVs=[i.val for i in Ninlvl if i]
            m=len(ndVs)
            if ndVs[0:int(m/2)]!=ndVs[:int(m/2)-1:-1]:
                 return False       
            NextNinlvl=[]
            for i in Ninlvl:
                if i:
                    NextNinlvl+=[i.left,i.right]
            Ninlvl=NextNinlvl
        return True

Recursive Solution:

# Definition for a  binary tree node
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    # @param root, a tree node
    # @return a boolean
    def smtc(self,T1,T2):
        if T1==T2==None:
            return True
        elif not T1 or not T2:
            return False
        elif T1.val==T2.val:
            return True if self.smtc(T1.left,T2.right) and self.smtc(T1.right,T2.left) else False
        else:
            return False
    def isSymmetric(self, root):
        if not root:
            return True
        return self.smtc(root.left,root.right)