24. Swap Nodes in Pairs
Problem
Given a linked list, swap every two adjacent nodes and return its head. You must solve the problem without modifying the values in the list's nodes (i.e., only nodes themselves may be changed.)
Example
Input: head = [1,2,3,4]
Output: [2,1,4,3]
[1] Code (22. 03. 20) (x)
// Runtime: 0 ms
// Memory Usage: 39.9 MB
// Ref : https://leetcode.com/submissions/detail/663391750
class Solution {
public ListNode swapPairs(ListNode head) {
if (head == null || head.next == null) {
return head;
}
ListNode temp = new ListNode();
temp.next = head;
head = head.next;
while (temp.next != null && temp.next.next != null) {
ListNode node1 = temp.next;
ListNode node2 = temp.next.next;
node1.next = node2.next;
node2.next = node1;
temp.next = node2;
temp = temp.next.next;
}
return head;
}
}
Review
-
25분 소요
이런 유형의 문제는 꼼꼼하게 코드를 작성하면 풀린다.