牛客网HOT200(一)

public class Solution {
    public ListNode ReverseList(ListNode head) {
    if(head == null){
        return null;
    }
        ListNode pre = null;
        ListNode cur = null;
        while(head != null){
            cur = head.next;
            head.next = pre;
            pre = head;
            head = cur;
        }
        return pre;
}
}

 public int[] MySort