Find a Corresponding Node of a Binary Tree in a Clone of That Tree
<p>Given two binary trees <code>original</code> and <code>cloned</code> and given a reference to a node <code>target</code> in the original tree.</p>

<p>The <code>cloned</code> tree is a <strong>copy of</strong> the <code>original</code> tree.</p>

<p>Return <em>a reference to the same node</em> in the <code>cloned</code> tree.</p>

<p><strong>Note</strong> that you are <strong>not allowed</strong> to change any of the two trees or the <code>target</code> node and the answer <strong>must be</strong> a reference to a node in the <code>cloned</code> tree.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/1300-1399/1379.Find%20a%20Corresponding%20Node%20of%20a%20Binary%20Tree%20in%20a%20Clone%20of%20That%20Tree/images/e1.png" style="width: 544px; height: 426px;" />
<pre>
<strong>Input:</strong> tree = [7,4,3,null,null,6,19], target = 3
<strong>Output:</strong> 3
<strong>Explanation:</strong> In all examples the original and cloned trees are shown. The target node is a green node from the original tree. The answer is the yellow node from the cloned tree.
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/1300-1399/1379.Find%20a%20Corresponding%20Node%20of%20a%20Binary%20Tree%20in%20a%20Clone%20of%20That%20Tree/images/e2.png" style="width: 221px; height: 159px;" />
<pre>
<strong>Input:</strong> tree = [7], target =  7
<strong>Output:</strong> 7
</pre>

<p><strong class="example">Example 3:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/1300-1399/1379.Find%20a%20Corresponding%20Node%20of%20a%20Binary%20Tree%20in%20a%20Clone%20of%20That%20Tree/images/e3.png" style="width: 459px; height: 486px;" />
<pre>
<strong>Input:</strong> tree = [8,null,6,null,5,null,4,null,3,null,2,null,1], target = 4
<strong>Output:</strong> 4
</pre>

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

<ul>
	<li>The number of nodes in the <code>tree</code> is in the range <code>[1, 10<sup>4</sup>]</code>.</li>
	<li>The values of the nodes of the <code>tree</code> are unique.</li>
	<li><code>target</code> node is a node from the <code>original</code> tree and is not <code>null</code>.</li>
</ul>

<p>&nbsp;</p>
<p><strong>Follow up:</strong> Could you solve the problem if repeated values on the tree are allowed?</p>
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(int x) { val = x; }
 * }
 */

class Solution {
    private TreeNode target;

    public final TreeNode getTargetCopy(
        final TreeNode original, final TreeNode cloned, final TreeNode target) {
        this.target = target;
        return dfs(original, cloned);
    }

    private TreeNode dfs(TreeNode root1, TreeNode root2) {
        if (root1 == null) {
            return null;
        }
        if (root1 == target) {
            return root2;
        }
        TreeNode res = dfs(root1.left, root2.left);
        return res == null ? dfs(root1.right, root2.right) : res;
    }
}