首頁 解題筆記 Leetcode Medium

⭐️⭐️⭐️

# 題目敘述

You are given the head of a linked list, and an integer k .

Return the head of the linked list after swapping the values of the kth node from the beginning and the kth node from the end (the list is 1-indexed).

# Example 1

Input: head = [1,2,3,4,5], k = 2
Output: [1,4,3,2,5]

# Example 2

Input: head = [7,9,6,6,7,8,3,0,9,5], k = 5
Output: [7,9,6,6,8,7,3,0,9,5]

# 解題思路

# Solution

// 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 swapNodes(ListNode head, int k) {
        ListNode start = head, end = head;
        
        for (int i = 1; i < k; i++) {
            start = start.next;
        }
        
        ListNode curr = start;
        while (curr.next != null) {
            curr = curr.next;
            end = end.next;
        }
        
        int temp = start.val;
        start.val = end.val;
        end.val = temp;
        
        return head;
    }
}




單字
** **
!! !!
片語 & 搭配詞
!! !!