题目描述
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.
方法思路
画了图就很好理解了
class Solution{
//Runtime: 2 ms, faster than 99.99%
//Memory Usage: 36.9 MB, less than 49.44%
public ListNode swapPairs(ListNode head) {
ListNode dummy = new ListNode(0);
dummy.next = head;
ListNode cur = dummy;
while(cur.next != null && cur.next.next != null){
ListNode first = cur.next;
ListNode second = cur.next.next;
first.next = second.next;
cur.next = second;
cur.next.next = first;
cur = cur.next.next;
}
return dummy.next;
}
}