链表只要注意不要丢失掉对节点引用;多可设置虚拟头结点简化引用的处理。
1.反转列表(leetcode206)
public class L206ReverseLinkedList { public static ListNode reverseList(ListNode head) { if(head == null){ return null; } ListNode pre = null; ListNode curr = head; ListNode next = head.next; while(curr.next!=null){ next = curr.next; curr.next = pre; pre = curr; curr = next; } curr.next = pre; ListNode res = curr; return res; } } class ListNode { int val; ListNode next; ListNode(int x) { val = x; } }