100.same-tree

Statement

简体中文English

Metadata

Link: 相同的树
Difficulty: Easy
Tag: 树 深度优先搜索 广度优先搜索 二叉树

给你两棵二叉树的根节点 p 和 q ，编写一个函数来检验这两棵树是否相同。

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：p = [1,2,3], q = [1,2,3]
输出：true

示例 2：

输入：p = [1,2], q = [1,null,2]
输出：false

示例 3：

输入：p = [1,2,1], q = [1,1,2]
输出：false

提示：

两棵树上的节点数目都在范围 [0, 100] 内
-10⁴ <= Node.val <= 10⁴

Metadata

Link: Same Tree
Difficulty: Easy
Tag: Tree Depth-First Search Breadth-First Search Binary Tree

Given the roots of two binary trees p and q, 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: p = [1,2,3], q = [1,2,3]
Output: true

Example 2:

Input: p = [1,2], q = [1,null,2]
Output: false

Example 3:

Input: p = [1,2,1], q = [1,1,2]
Output: false

Constraints:

The number of nodes in both trees is in the range [0, 100].
-10⁴ <= Node.val <= 10⁴

Solution

Python 3

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def dfs(self, l: TreeNode, r: TreeNode) -> bool:
        if not l and not r:
            return True

        if not l or not r:
            return False

        if l.val != r.val:
            return False

        return self.dfs(l.left, r.left) and self.dfs(l.right, r.right)

    def isSameTree(self, p: TreeNode, q: TreeNode) -> bool:
        return self.dfs(p, q)

最后更新: October 11, 2023