Same Tree

Question

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:

Example 2:

Solution

class Solution:
    def isSameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:
        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)

Time complexity: $O(n)$ — n is the number of nodes
Space complexity: $O(logn)$ — $logn$ for the height of the tree since recursion stack