Convert Sorted List to Binary Search Tree

Convert Sorted List to Binary Search Tree

Given a singly linked list where elements is sorted in ascending order, convert it to a height balanced BST.

I began to time out the problem, and then I thought of an opportunistic approach. To convert an array, and then use the method of the above question

1 /**2 * Definition for singly-linked list.3 * public class ListNode {4 * int val;5 * ListNode Next;6 * ListNode (int x) {val = x; next = null;}7  * }8  */9 /**Ten * Definition for binary tree One * public class TreeNode { A * int val; - * TreeNode left; - * TreeNode right; the * TreeNode (int x) {val = x;} -  * } -  */ -  Public classSolution { +      PublicTreeNode Root; -      Public intnums[]; +      A      PublicTreeNode Sortedlisttobst (ListNode head) { atListNode temp =head; -         intLength = 0; -          while(Temp! =NULL){ -Length + +; -temp =Temp.next;  -         } inNums =New int[length]; -temp =head; to          for(inti = 0; i < nums.length; i++){ +Nums[i] =Temp.val; -temp =Temp.next; the         } *         returnSortedarraytobst (nums); $     }Panax Notoginseng  -      PublicTreeNode Sortedarraytobst (int[] num) { the         if(Num.length = = 0) +             returnRoot; A         if(1 = =num.length) { the             return NewTreeNode (num[0]); +         } -         intMiddle = NUM.LENGTH/2; $Root =NewTreeNode (Num[middle]); $          -Createbst (num, 0, middle-1); -Createbst (num, middle + 1, num.length-1); the         returnRoot; -     }Wuyi      the     /** - * Create a binary lookup tree based on the NUM array Wu      * @paramNum -      * @paramStart About      * @paramEnd $      */ -     Private voidCreatebst (intNum[],intStartintend) { -         intMiddle = 0; -         if(Start <= end && start >= 0 && End <num.length) { AMiddle = (start + end)/2; +              the Insertnode (Root, Num[middle]); -              $Createbst (num, start, middle-1); theCreatebst (num, middle + 1, end); the         } the     } the      -     /** in * Insert value into the BST two fork lookup tree referred to as root the      * @paramRoot the      * @paramvalue About      */ the     Private voidInsertnode (TreeNode root,intvalue) {         the         if(Value > Root.val) {//larger than the root node, inserted in the right sub-tree the             if(Root.right = =NULL){ +Root.right =NewTreeNode (value); -}Else{ theRoot =Root.right;Bayi Insertnode (root, value); the             } the         } -         Else{ -             if(Root.left = =NULL){ theRoot.left =NewTreeNode (value); the}Else{ theRoot =Root.left; theInsertnode (root, value);//Insert the left subtree smaller than the root node -             } the         } the     } the     94     /** the * First Order traversal the      * @paramRoot the      */98      Public voidpretravel (TreeNode root) { About         if(Root! =NULL){ - //System.out.print (Root.val + "");101 Pretravel (root.left);102 Pretravel (root.right);103         }104     } the}

Convert Sorted List to Binary Search Tree