Same Tree
<p>Given the roots of two binary trees <code>p</code> and <code>q</code>, write a function to check if they are the same or not.</p>

<p>Two binary trees are considered the same if they are structurally identical, and the nodes have the same value.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0100-0199/0100.Same%20Tree/images/ex1.jpg" style="width: 622px; height: 182px;" />
<pre>
<strong>Input:</strong> p = [1,2,3], q = [1,2,3]
<strong>Output:</strong> true
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0100-0199/0100.Same%20Tree/images/ex2.jpg" style="width: 382px; height: 182px;" />
<pre>
<strong>Input:</strong> p = [1,2], q = [1,null,2]
<strong>Output:</strong> false
</pre>

<p><strong class="example">Example 3:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0100-0199/0100.Same%20Tree/images/ex3.jpg" style="width: 622px; height: 182px;" />
<pre>
<strong>Input:</strong> p = [1,2,1], q = [1,1,2]
<strong>Output:</strong> false
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The number of nodes in both trees is in the range <code>[0, 100]</code>.</li>
	<li><code>-10<sup>4</sup> &lt;= Node.val &lt;= 10<sup>4</sup></code></li>
</ul>
Tree; Depth-First Search; Breadth-First Search; Binary Tree
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if (p == q) return true;
        if (p == null || q == null || p.val != q.val) return false;
        return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
    }
}