public ListNode sortList(ListNode head){
		if(head == null || head.next == null) return head;
		ListNode point = head;
		int[] arr = new int[9999];
		int idx = 0;
		while(point != null){
			arr[idx++] = point.val;
			point = point.next;
		}
		quickSort(arr, 0, idx-1);
		point = head;
		for(int i = 0; i<idx; i++){
			point.val = arr[i];
			point = point.next;
		}
		return head; 
	}