LeetCode-convert-sorted-list-to-binary-search-tree

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

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; next = null; }
 * }
 */
/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public TreeNode sortedListToBST(ListNode head)
    {
        if(head==null) return null;
        if(head.next == null) return new TreeNode(head.val);
        ListNode slow = head;
        ListNode fast = head.next;
        while(fast.next!=null && fast.next.next!=null)
        {
            slow = slow.next;
            fast = fast.next.next;
        }
        TreeNode root = new TreeNode(slow.next.val);
        root.right = sortedListToBST(slow.next.next);
        slow.next = null;
        root.left = sortedListToBST(head);
        return root;
    }
}