100. Same Tree

Given two binary trees, write a function to check if they are the same or not.

Two binary trees are considered the same if they are structurally identical and the nodes have the same value.

Example 1:

Input:     1         1
          /        / 
         2   3     2   3

        [1,2,3],   [1,2,3]

Output: true

Example 2:

Input:     1         1
          /           
         2             2

        [1,2],     [1,null,2]

Output: false

Example 3:

Input:     1         1
          /        / 
         2   1     1   2

        [1,2,1],   [1,1,2]

Output: false

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

class Solution(object):
    def isSameTree(self, p, q):
        """
        :type p: TreeNode
        :type q: TreeNode
        :rtype: bool
        """
        if(p == None and q == None):
            return True
        if(p == None or q == None):
            return False
        if(p.val != q.val):
            return False
        return self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)