/**

* LeetCode 617 https://leetcode.com/problems/merge-two-binary-trees

*

*/

/**

* 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 TreeNode mergeTrees(TreeNode root1, TreeNode root2) {

if (root1 == null && root2 == null) { return null;}

if (root1 == null) { return root2; }

if (root2 == null) { return root1; }

TreeNode mergedTree = new TreeNode(root1.val + root2.val);

mergedTree.left = mergeTrees(root1.left, root2.left);

mergedTree.right = mergeTrees(root1.right, root2.right);

return mergedTree;

}

}