Leetcode100. 相同的樹

給定兩個二叉樹，編寫一個函數來檢驗它們是否相同。

如果兩個樹在結構上相同，並且節點具有相同的值，則認爲它們是相同的。

示例 1:

輸入:       1         1
          / \       / \
         2   3     2   3

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

輸出: true
示例 2:

輸入:      1          1
          /           \
         2             2

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

輸出: 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 and q!=None)or(p!= None and 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)