Problem Difficulty Level: Medium

Author: Naganathan05

Divide and Conquer/109. Convert Sorted List to Binary Search Tree.cpp

@@ -0,0 +1,37 @@
+/*------------------------
+  Time Complexity: O(n)
+  Space Complexity: O(n)
+--------------------------*/
+
+class Solution {
+public:
+    TreeNode* constructTree(unordered_map<int, ListNode*> &listMapping, int low, int high){
+        if(low > high) return NULL;
+
+        int mid = low + (high - low) / 2;
+        ListNode* midNode = listMapping[mid];
+        TreeNode* newNode = new TreeNode(midNode -> val);
+
+        newNode -> left = constructTree(listMapping, low, mid - 1);
+        newNode -> right = constructTree(listMapping, mid + 1, high);
+        return newNode;
+    }
+
+    TreeNode* sortedListToBST(ListNode* head) {
+        unordered_map<int, ListNode*> listMapping;
+        ListNode* currNode = head;
+        int index = 0;
+
+        while(currNode){
+            listMapping[index] = currNode;
+            currNode = currNode -> next;
+            index += 1;
+        }
+        return constructTree(listMapping, 0, index - 1);
+    }
+};
+
+/*
+Question Link: https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree/
+Author: M.R.Naganathan
+*/