[LeetCode] 617. Merge Two Binary Trees

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

 

class Solution {
    public TreeNode mergeTrees(TreeNode root1, TreeNode root2) {
        TreeNode head = root1;
        
        if(root1==null && root2==null) return null;
        if(root1==null && root2!=null) return root2;
        if(root1!=null && root2==null) return root1;
        
        root1.val+=root2.val;
        root1.left = mergeTrees(root1.left, root2.left);
        root1.right = mergeTrees(root1.right, root2.right);
        
        return root1;
    }
}