0100. Same Tree

https://leetcode.com/problems/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

ac

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        // exit
        if (p == null && q == null) return true;
        else if (p == null || q == null) return false;

        if (p.val != q.val) return false;

        return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
    }
}