solve problem Convert Sorted Array To Binary Search Tree

Author: P-ppc

README.md

@@ -17,4 +17,5 @@ All solutions will be accepted!
 |104|[Maximum Depth Of Binary Tree](https://leetcode-cn.com/problems/maximum-depth-of-binary-tree/description/)|[java/py/js](./algorithms/MaximumDepthOfBinaryTree)|Easy|
 |617|[Merge Two Binary Trees](https://leetcode-cn.com/problems/merge-two-binary-trees/description/)|[java/py/js](./algorithms/MergeTwoBinaryTrees)|Easy|
 |226|[Invert Binary Tree](https://leetcode-cn.com/problems/invert-binary-tree/description/)|[java/py/js](./algorithms/InvertBinaryTree)|Easy|
-|693|[Binary Number With Alternating Bits](https://leetcode-cn.com/problems/binary-number-with-alternating-bits/description/)|[java/py/js](./algorithms/BinaryNumberWithAlternatingBits)|Easy|
+|693|[Binary Number With Alternating Bits](https://leetcode-cn.com/problems/binary-number-with-alternating-bits/description/)|[java/py/js](./algorithms/BinaryNumberWithAlternatingBits)|Easy|
+|108|[Convert Sorted Array To Binary Search Tree](https://leetcode-cn.com/problems/convert-sorted-array-to-binary-search-tree/description/)|[java/py/js](./algorithms/ConvertSortedArrayToBinarySearchTree)|Easy|

algorithms/ConvertSortedArrayToBinarySearchTree/README.md

@@ -0,0 +1,2 @@
+# Convert Sorted Array To Binary Search Tree
+Use recursion to solve this problem

algorithms/ConvertSortedArrayToBinarySearchTree/Solution.java

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+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public TreeNode sortedArrayToBST(int[] nums) {
+        if (nums.length == 0) {
+            return null;
+        }
+        TreeNode root = new TreeNode(nums[nums.length / 2]);
+        root.left = sortedArrayToBST(Arrays.copyOfRange(nums, 0, nums.length / 2));
+        root.right = sortedArrayToBST(Arrays.copyOfRange(nums, nums.length / 2 + 1, nums.length));
+        return root;
+    }
+}

algorithms/ConvertSortedArrayToBinarySearchTree/solution.js

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+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {number[]} nums
+ * @return {TreeNode}
+ */
+var sortedArrayToBST = function(nums) {
+    if (nums.length === 0) {
+        return null
+    }
+    let root = new TreeNode(nums[parseInt(nums.length / 2)])
+    root.left = sortedArrayToBST(nums.slice(0, parseInt(nums.length / 2)))
+    root.right = sortedArrayToBST(nums.slice(parseInt(nums.length / 2) + 1, nums.length))
+    return root
+};

algorithms/ConvertSortedArrayToBinarySearchTree/solution.py

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+# Definition for a binary tree node.
+# class TreeNode(object):
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution(object):
+    def sortedArrayToBST(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: TreeNode
+        """
+        # for a binary search tree
+        # this root is middle
+        if len(nums) == 0:
+            return None
+        root = TreeNode(nums[len(nums) / 2])
+        root.left = self.sortedArrayToBST(nums[0 : (len(nums) / 2)])
+        root.right = self.sortedArrayToBST(nums[len(nums) / 2 + 1 : len(nums)])
+        return root