convert_sorted_array_to_binary_search_tree

Author: hitzzc

README.md

@@ -94,6 +94,7 @@ Golang solution for leetcode. For each problem, there is a simple *_test.go to t
 #### [105. construct binary tree from preorder and inorder traversal](https://github.com/hitzzc/go-leetcode/tree/master/construct_binary_tree_from_preorder_and_inorder_traversal)
 #### [106. construct binary tree from inorder and postorder traversal](https://github.com/hitzzc/go-leetcode/tree/master/construct_binary_tree_from_inorder_and_postorder_traversal)
 #### [107. Binary Tree Level Order Traversal II](https://github.com/hitzzc/go-leetcode/tree/master/binary_tree_level_order_traversal_II)
+#### [108. Convert Sorted Array to Binary Search Tree](https://github.com/hitzzc/go-leetcode/tree/master/convert_sorted_array_to_binary_search_tree)
 
 
 

convert_sorted_array_to_binary_search_tree/convert_sorted_array_to_binary_search_tree.go

@@ -0,0 +1,25 @@
+package convert_sorted_array_to_binary_search_tree
+
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func sortedArrayToBST(nums []int) *TreeNode {
+	return helper(nums, 0, len(nums)-1)
+}
+
+func helper(nums []int, i, j int) *TreeNode {
+	if len(nums) == 0 || i > j || i < 0 || j >= len(nums) {
+		return nil
+	}
+	if i == j {
+		return &TreeNode{Val: nums[i]}
+	}
+	mid := i + (j-i)/2
+	root := &TreeNode{Val: nums[mid]}
+	root.Left = helper(nums, i, mid-1)
+	root.Right = helper(nums, mid+1, j)
+	return root
+}