same_tree

# 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: Optional[TreeNode], q: Optional[TreeNode]) -> bool:
        
        def same(p,q):
            if not p and not q: #indicates neither root exists so return True
                return True
            if (not p and q) or (not q and p): #if one node exists and the other doesnt then theyre not equivalent
                return False
            if p.val != q.val: #if both nodes exists and the value is different, then not equal
                return False
            return same(p.left, q.left) and same(p.right, q.right)
        return same(p,q)

"""
100. Same Tree
Easy
Topics
Companies

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

"""