add 108

Author: shishishu

README.md

@@ -45,3 +45,4 @@ Idx | Date | Question | Python| Java | Domain | Tag | Difficulty | Remark
 039|20200425|[705. Design HashSet](https://leetcode.com/problems/design-hashset/)|[705p](https://github.com/shishishu/leetcode-python-java/blob/master/ipynb_files/705_Design_HashSet.ipynb)|[705j](https://github.com/shishishu/leetcode-python-java/blob/master/java_codes/705/Solution.java)|Hash| |Easy
 040|20200425|[13. Roman to Integer](https://leetcode.com/problems/roman-to-integer/)|[013p](https://github.com/shishishu/leetcode-python-java/blob/master/ipynb_files/013_Roman_to_Integer.ipynb)|[013j](https://github.com/shishishu/leetcode-python-java/blob/master/java_codes/013/Solution.java)|Math| |Easy
 041|20200425|[12. Integer to Roman](https://leetcode.com/problems/integer-to-roman/)|[012p](https://github.com/shishishu/leetcode-python-java/blob/master/ipynb_files/012_Integer_to_Roman.ipynb)|[012j](https://github.com/shishishu/leetcode-python-java/blob/master/java_codes/012/Solution.java)|Math| |Medium
+042|20200627|[108. Convert Sorted Array to Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/)|[108p](https://github.com/shishishu/leetcode-python-java/blob/master/ipynb_files/108_Convert_Sorted_Array_to_Binary_Search_Tree.ipynb)|[108j](https://github.com/shishishu/leetcode-python-java/blob/master/java_codes/108/Solution.java)|BST|Recursive|Easy

images/108_Q.PNG

@@ -0,0 +1,34 @@
+//Definition for a binary tree node.
+class TreeNode {
+    int val;
+    TreeNode left;
+    TreeNode right;
+    TreeNode() {}
+    TreeNode(int val) { this.val = val; }
+    TreeNode(int val, TreeNode left, TreeNode right) {
+        this.val = val;
+        this.left = left;
+        this.right = right;
+    }
+}
+
+class Solution {
+    public TreeNode sortedArrayToBST(int[] nums) {
+        return convert(nums, 0, nums.length - 1);
+    }
+
+    private TreeNode convert(int[] nums, int left, int right){
+        if (left > right){
+            return null;
+        }
+        int mid = (left + right) / 2;
+        TreeNode node = new TreeNode(nums[mid]);
+        node.left = convert(nums, left, mid - 1);
+        node.right = convert(nums, mid + 1, right);
+        return node;
+    }
+}
+
+
+
+

images/108_S1.PNG

@@ -45,6 +45,7 @@
       <sourceFolder url="file://$MODULE_DIR$/705" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/013" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/012" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/108" isTestSource="false" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />