LC-24
[24. 两两交换链表中的节点](https://leetcode-cn.com/problems/swap-nodes-in-pairs/)
给你一个链表,两两交换其中相邻的节点,并返回交换后链表的头节点。你必须在不修改节点内部的值的情况下完成本题(即,只能进行节点交换)。
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode() {}
* ListNode(int val) { this.val = val; }
* ListNode(int val, ListNode next) { this.val = val; this.next = next; }
* }
*/
class Solution {
public ListNode swapPairs(ListNode head) {
ListNode dummyHead = new ListNode(0);
dummyHead.next = head;
ListNode temp = dummyHead;
while(temp.next != null && temp.next.next != null) {
ListNode node1 = temp.next;
ListNode node2 = temp.next.next;
temp.next =node2;
node1.next = node2.next;
node2.next = node1;
temp = node1;
}
return dummyHead.next;
}
}
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, val=0, next=None):
# self.val = val
# self.next = next
class Solution:
def swapPairs(self, head: ListNode) -> ListNode:
dummyHead = ListNode(0)
dummyHead.next = head
temp = dummyHead
while temp.next != None and temp.next.next != None:
node1 = temp.next
node2 = temp.next.next
temp.next = node2
node1.next = node2.next
node2.next = node1
temp = node1
return dummyHead.next