Create 0701. Insert into a Binary Search Tree

Author: haibarawu

0701. Insert into a Binary Search Tree

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+/****************************************
+701. Insert into a Binary Search Tree
+
+Difficulty: Medium
+
+Given the root node of a binary search tree (BST) and a value to be inserted into the tree, 
+insert the value into the BST. 
+Return the root node of the BST after the insertion. 
+It is guaranteed that the new value does not exist in the original BST.
+
+Note that there may exist multiple valid ways for the insertion, 
+as long as the tree remains a BST after insertion. 
+You can return any of them.
+
+For example, 
+Given the tree:
+        4
+       / \
+      2   7
+     / \
+    1   3
+And the value to insert: 5
+You can return this binary search tree:
+         4
+       /   \
+      2     7
+     / \   /
+    1   3 5
+
+This tree is also valid:
+         5
+       /   \
+      2     7
+     / \   
+    1   3
+         \
+          4
+****************************************/
+
+
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public TreeNode insertIntoBST(TreeNode root, int val) {
+        if (root == null) {
+            return new TreeNode(val);
+        }
+        
+        if (val < root.val) {
+            root.left = insertIntoBST(root.left, val);
+        }
+        else {
+            root.right = insertIntoBST(root.right, val);
+        }
+        
+        return root;
+    }
+}
+