108. Convert Sorted Array to Binary Search Tree (java)

Author: bluesword12350

solution/0108.Convert Sorted Array to Binary Search Tree/Solution.java

@@ -0,0 +1,15 @@
+class Solution {
+    public TreeNode sortedArrayToBST(int[] nums) {
+        int len = nums.length;
+        if (len == 0) return null;
+        return helper(nums, 0, len - 1);
+    }
+    private TreeNode helper(int[] arr, int start, int end) {
+        if (start > end) return null;
+        int middle = (end + start) / 2;
+        TreeNode helperRoot = new TreeNode(arr[middle]);
+        helperRoot.left = helper(arr, start, middle - 1);
+        helperRoot.right = helper(arr, middle + 1, end);
+        return helperRoot;
+    }
+}