Add solution #108

Author: JoshCrozier

Diff for: README.md

@@ -103,6 +103,7 @@
 101|[Symmetric Tree](./0101-symmetric-tree.js)|Easy|
 102|[Binary Tree Level Order Traversal](./0102-binary-tree-level-order-traversal.js)|Medium|
 104|[Maximum Depth of Binary Tree](./0104-maximum-depth-of-binary-tree.js)|Easy|
+108|[Convert Sorted Array to Binary Search Tree](./0108-convert-sorted-array-to-binary-search-tree.js)|Easy|
 110|[Balanced Binary Tree](./0110-balanced-binary-tree.js)|Easy|
 111|[Minimum Depth of Binary Tree](./0111-minimum-depth-of-binary-tree.js)|Easy|
 112|[Path Sum](./0112-path-sum.js)|Easy|

Diff for: solutions/0108-convert-sorted-array-to-binary-search-tree.js

@@ -0,0 +1,31 @@
+/**
+ * 108. Convert Sorted Array to Binary Search Tree
+ * https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/
+ * Difficulty: Easy
+ *
+ * Given an integer array nums where the elements are sorted in ascending order, convert it
+ * to a height-balanced binary search tree.
+ */
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {number[]} nums
+ * @return {TreeNode}
+ */
+var sortedArrayToBST = function(nums) {
+  if (!nums.length) return null;
+
+  const middleIndex = Math.floor(nums.length / 2);
+  const root = new TreeNode(nums[middleIndex]);
+  root.left = sortedArrayToBST(nums.slice(0, middleIndex));
+  root.right = sortedArrayToBST(nums.slice(middleIndex + 1));
+
+  return root;
+};