symmetric-tree.txt

# 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
        self.flipTree(root.right)
        return self.isTheSame(root.left, root.right)
	
    def flipTree(self, root):
        if root != None:
            temp = root.left
            root.left = root.right
            root.right = temp
            self.flipTree(root.left)
            self.flipTree(root.right)
			
    def isTheSame(self, p, q):
        if (p == None and q != None) or (p != None and q == None) or (p != None and q != None and p.val != q.val):
            return False
        elif p == None and q == None:
            return True
        return self.isTheSame(p.left, q.left) and self.isTheSame(p.right, q.right)