答案

/**
 * 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 {
    int []array;
    public TreeNode sortListToBST(int start ,int end)
    {
        int middle=start+((end-start)>>1);
        TreeNode root=new TreeNode(array[middle]);
        if(middle>start)
        {
            root.left=sortListToBST(start,middle-1);
        }
        if(middle<end)
        {
            root.right=sortListToBST(middle+1,end);
        }
        return root;
    }
    public TreeNode sortedListToBST(ListNode head) {
        if(head==null)
        {
            return null;
        }
        array=new int[65535];
        int N=0;
        while(head!=null)
        {
            array[N++]=head.val;
            head=head.next;
        }
        return sortListToBST(0,N-1);
    }
}