leetcode 100. 相同的树 (python)

给定两个二叉树，编写一个函数来检验它们是否相同。

如果两个树在结构上相同，并且节点具有相同的值，则认为它们是相同的。

示例 1:

输入:       1         1
          / \       / \
         2   3     2   3

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

输出: true

示例 2:

输入:      1          1
          /           \
         2             2

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

输出: false

示例 3:

输入:       1         1
          / \       / \
         2   1     1   2

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

输出: false

---

本题主要注意下面一种情况即可，其他的就每个节点比较就好。

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

代码如下

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

class Solution:
    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:#[1,2][1,null,2]
            return False
        if p.val == q.val:
            return self.isSameTree(p.left,q.left) and self.isSameTree(p.right,q.right)
        else :
            return False# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    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:#[1,2][1,null,2]
            return False
        if p.val == q.val:
            return self.isSameTree(p.left,q.left) and self.isSameTree(p.right,q.right)
        else :
            return False