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Author: 10coder

MergeBinaryTrees.java

@@ -0,0 +1,40 @@
+public class MergeBinaryTrees {
+
+    public TreeNode mergeTrees(TreeNode root1, TreeNode root2) {
+        //assign non null root to head
+        TreeNode head=root1!=null?root1:root2;
+        //if either root is null skip merging
+        if(root1!=null && root2!=null)
+            merge(root1,root2);
+        return head;
+    }
+
+    public void merge(TreeNode root1, TreeNode root2) {
+        //nothing to merge
+        if(root1==null && root2==null) {
+            return;
+        }
+        //merge both
+        if(root1!=null && root2!=null) {
+            root1.val+=root2.val;
+        }
+
+        //if both have left values merge them otherwise assign non null value to the left branch
+        if(root1.left!=null && root2.left!=null) {
+            merge(root1.left,root2.left);
+        }
+        //if root1 left is null assign root1 left
+        if(root1.left==null) {
+            root1.left=root2.left;
+        }
+
+        //if both have right values merge them otherwise assign non null value to the right branch
+        if(root1.right!=null && root2.right!=null) {
+            merge(root1.right,root2.right);
+        }
+        if(root1.right==null) {
+            root1.right=root2.right;
+        }
+
+    }
+}