1721. Swapping Nodes in a Linked List Medium

1/**
2 * [1721] Swapping Nodes in a Linked List
3 *
4 * You are given the head of a linked list, and an integer k.
5 * Return the head of the linked list after swapping the values of the k^th node from the beginning and the k^th node from the end (the list is 1-indexed).
6 *  
7 * Example 1:
8 * <img alt="" src="https://assets.leetcode.com/uploads/2020/09/21/linked1.jpg" style="width: 400px; height: 112px;" />
9 * Input: head = [1,2,3,4,5], k = 2
10 * Output: [1,4,3,2,5]
11 * 
12 * Example 2:
13 * 
14 * Input: head = [7,9,6,6,7,8,3,0,9,5], k = 5
15 * Output: [7,9,6,6,8,7,3,0,9,5]
16 * 
17 *  
18 * Constraints:
19 * 
20 * 	The number of nodes in the list is n.
21 * 	1 <= k <= n <= 10^5
22 * 	0 <= Node.val <= 100
23 * 
24 */
25pub struct Solution {}
26use crate::util::linked_list::{ListNode, to_list};
27
28// problem: https://leetcode.com/problems/swapping-nodes-in-a-linked-list/
29// discuss: https://leetcode.com/problems/swapping-nodes-in-a-linked-list/discuss/?currentPage=1&orderBy=most_votes&query=
30
31// submission codes start here
32
33// Definition for singly-linked list.
34// #[derive(PartialEq, Eq, Clone, Debug)]
35// pub struct ListNode {
36//   pub val: i32,
37//   pub next: Option<Box<ListNode>>
38// }
39// 
40// impl ListNode {
41//   #[inline]
42//   fn new(val: i32) -> Self {
43//     ListNode {
44//       next: None,
45//       val
46//     }
47//   }
48// }
49impl Solution {
50    pub fn swap_nodes(head: Option<Box<ListNode>>, k: i32) -> Option<Box<ListNode>> {
51        Some(Box::new(ListNode::new(0)))
52    }
53}
54
55// submission codes end
56
57#[cfg(test)]
58mod tests {
59    use super::*;
60
61    #[test]
62    fn test_1721() {
63    }
64}
65