0100-same-tree¶

Description¶

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)¶

# 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 isSameTree(self, p: TreeNode | None, q: TreeNode | None) -> bool:
        # p q 
        # both None True
        # or None False
        # not eual = false
        # recurse
        if not p and not q:
            return True

        if not p or not q:
            return False

        if p.val != q.val:
            return False
        
        return self.isSameTree(p.left, q.left) and self.isSameTree(p.right  , q.right) 