Create 0108-convert-sorted-array-to-binary-search-tree.kt

Author: a93a

kotlin/0108-convert-sorted-array-to-binary-search-tree.kt

@@ -0,0 +1,29 @@
+/**
+ * Example:
+ * var ti = TreeNode(5)
+ * var v = ti.`val`
+ * Definition for a binary tree node.
+ * class TreeNode(var `val`: Int) {
+ *     var left: TreeNode? = null
+ *     var right: TreeNode? = null
+ * }
+ */
+class Solution {
+    fun sortedArrayToBST(nums: IntArray): TreeNode? {
+        
+        fun createTree(left: Int, right: Int): TreeNode? {
+
+            if(left > right) return null
+            else if(left == right) return TreeNode(nums[left])
+
+            val mid = (left + right) / 2
+            val node = TreeNode(nums[mid])
+            node.left = createTree(left, mid-1)
+            node.right = createTree(mid+1, right)
+
+            return node
+        }
+
+        return createTree(0, nums.lastIndex)
+    }
+}