Create 108. Convert Sorted Array to Binary Search Tree.java

Author: futurus

108. Convert Sorted Array to Binary Search Tree.java

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+// https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree
+
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+public class Solution {
+    public TreeNode helper(int[] nums) {
+        TreeNode root = null;
+        
+        if (nums.length > 0) {
+            int mid = (nums.length - 1) / 2;
+            root = new TreeNode(nums[mid]);
+            root.left = helper(Arrays.copyOfRange(nums, 0, mid));
+            root.right = helper(Arrays.copyOfRange(nums, mid + 1, nums.length));
+        } 
+        return root;
+    }
+    
+    public TreeNode sortedArrayToBST(int[] nums) {
+        return helper(nums);
+    }
+}