LeetCode-24.Swap Nodes in Pairs

Given a linked list, swap every two adjacent nodes and return its head.

You may not modify the values in the list's nodes, only nodes itself may be changed.

 Example:

Given 1->2->3->4, you should return the list as 2->1->4->3.

public ListNode swapPairs(ListNode head) {//链表my
        ListNode nhead = new ListNode(0);
        nhead.next=head;
        ListNode cur=head;
        ListNode pre = nhead;
        while(null!= cur&&null!=cur.next){
            pre.next = cur.next;
            cur.next=pre.next.next;
            pre.next.next=cur;
            pre=cur;
            cur=cur.next;
        }
        return nhead.next;
    }

方法一样，但可读性更高的代码

public ListNode swapPairs1(ListNode head) {
        ListNode nhead = new ListNode(0);
        nhead.next=head;
        ListNode pre = nhead;
        while(null!= pre.next&&null!=pre.next.next){
            ListNode fitst= pre.next;
            ListNode second = pre.next.next;
            pre.next=second;
            fitst.next=second.next;
            second.next=fitst;
            pre=fitst;
        }
        return nhead.next;
    }

 

相关题

链表反转 LeetCode206  https://www.cnblogs.com/zhacai/p/10429295.html

进阶题

每 k 个节点一组翻转链表 LeetCode25  https://www.cnblogs.com/zhacai/p/10563446.html