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            "questionId": "528",
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            "title": "Swapping Nodes in a Linked List",
            "titleSlug": "swapping-nodes-in-a-linked-list",
            "content": "<p>You are given the <code>head</code> of a linked list, and an integer <code>k</code>.</p>\n\n<p>Return <em>the head of the linked list after <strong>swapping</strong> the values of the </em><code>k<sup>th</sup></code> <em>node from the beginning and the </em><code>k<sup>th</sup></code> <em>node from the end (the list is <strong>1-indexed</strong>).</em></p>\n\n<p>&nbsp;</p>\n<p><strong>Example 1:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2020/09/21/linked1.jpg\" style=\"width: 400px; height: 112px;\" />\n<pre>\n<strong>Input:</strong> head = [1,2,3,4,5], k = 2\n<strong>Output:</strong> [1,4,3,2,5]\n</pre>\n\n<p><strong>Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> head = [7,9,6,6,7,8,3,0,9,5], k = 5\n<strong>Output:</strong> [7,9,6,6,8,7,3,0,9,5]\n</pre>\n\n<p>&nbsp;</p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li>The number of nodes in the list is <code>n</code>.</li>\n\t<li><code>1 &lt;= k &lt;= n &lt;= 10<sup>5</sup></code></li>\n\t<li><code>0 &lt;= Node.val &lt;= 100</code></li>\n</ul>\n",
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            "difficulty": "Medium",
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            "similarQuestions": "[{\"title\": \"Remove Nth Node From End of List\", \"titleSlug\": \"remove-nth-node-from-end-of-list\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Swap Nodes in Pairs\", \"titleSlug\": \"swap-nodes-in-pairs\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Reverse Nodes in k-Group\", \"titleSlug\": \"reverse-nodes-in-k-group\", \"difficulty\": \"Hard\", \"translatedTitle\": null}]",
            "exampleTestcases": "[1,2,3,4,5]\n2\n[7,9,6,6,7,8,3,0,9,5]\n5",
            "categoryTitle": "Algorithms",
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                {
                    "name": "Linked List",
                    "slug": "linked-list",
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                    "__typename": "TopicTagNode"
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                {
                    "name": "Two Pointers",
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                {
                    "lang": "C++",
                    "langSlug": "cpp",
                    "code": "/**\n * Definition for singly-linked list.\n * struct ListNode {\n *     int val;\n *     ListNode *next;\n *     ListNode() : val(0), next(nullptr) {}\n *     ListNode(int x) : val(x), next(nullptr) {}\n *     ListNode(int x, ListNode *next) : val(x), next(next) {}\n * };\n */\nclass Solution {\npublic:\n    ListNode* swapNodes(ListNode* head, int k) {\n        \n    }\n};",
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                },
                {
                    "lang": "Java",
                    "langSlug": "java",
                    "code": "/**\n * Definition for singly-linked list.\n * public class ListNode {\n *     int val;\n *     ListNode next;\n *     ListNode() {}\n *     ListNode(int val) { this.val = val; }\n *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }\n * }\n */\nclass Solution {\n    public ListNode swapNodes(ListNode head, int k) {\n        \n    }\n}",
                    "__typename": "CodeSnippetNode"
                },
                {
                    "lang": "Python",
                    "langSlug": "python",
                    "code": "# Definition for singly-linked list.\n# class ListNode(object):\n#     def __init__(self, val=0, next=None):\n#         self.val = val\n#         self.next = next\nclass Solution(object):\n    def swapNodes(self, head, k):\n        \"\"\"\n        :type head: ListNode\n        :type k: int\n        :rtype: ListNode\n        \"\"\"\n        ",
                    "__typename": "CodeSnippetNode"
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                {
                    "lang": "Python3",
                    "langSlug": "python3",
                    "code": "# Definition for singly-linked list.\n# class ListNode:\n#     def __init__(self, val=0, next=None):\n#         self.val = val\n#         self.next = next\nclass Solution:\n    def swapNodes(self, head: Optional[ListNode], k: int) -> Optional[ListNode]:\n        ",
                    "__typename": "CodeSnippetNode"
                },
                {
                    "lang": "C",
                    "langSlug": "c",
                    "code": "/**\n * Definition for singly-linked list.\n * struct ListNode {\n *     int val;\n *     struct ListNode *next;\n * };\n */\n\n\nstruct ListNode* swapNodes(struct ListNode* head, int k){\n\n}",
                    "__typename": "CodeSnippetNode"
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                {
                    "lang": "C#",
                    "langSlug": "csharp",
                    "code": "/**\n * Definition for singly-linked list.\n * public class ListNode {\n *     public int val;\n *     public ListNode next;\n *     public ListNode(int val=0, ListNode next=null) {\n *         this.val = val;\n *         this.next = next;\n *     }\n * }\n */\npublic class Solution {\n    public ListNode SwapNodes(ListNode head, int k) {\n        \n    }\n}",
                    "__typename": "CodeSnippetNode"
                },
                {
                    "lang": "JavaScript",
                    "langSlug": "javascript",
                    "code": "/**\n * Definition for singly-linked list.\n * function ListNode(val, next) {\n *     this.val = (val===undefined ? 0 : val)\n *     this.next = (next===undefined ? null : next)\n * }\n */\n/**\n * @param {ListNode} head\n * @param {number} k\n * @return {ListNode}\n */\nvar swapNodes = function(head, k) {\n    \n};",
                    "__typename": "CodeSnippetNode"
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                {
                    "lang": "Ruby",
                    "langSlug": "ruby",
                    "code": "# Definition for singly-linked list.\n# class ListNode\n#     attr_accessor :val, :next\n#     def initialize(val = 0, _next = nil)\n#         @val = val\n#         @next = _next\n#     end\n# end\n# @param {ListNode} head\n# @param {Integer} k\n# @return {ListNode}\ndef swap_nodes(head, k)\n    \nend",
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                {
                    "lang": "Swift",
                    "langSlug": "swift",
                    "code": "/**\n * Definition for singly-linked list.\n * public class ListNode {\n *     public var val: Int\n *     public var next: ListNode?\n *     public init() { self.val = 0; self.next = nil; }\n *     public init(_ val: Int) { self.val = val; self.next = nil; }\n *     public init(_ val: Int, _ next: ListNode?) { self.val = val; self.next = next; }\n * }\n */\nclass Solution {\n    func swapNodes(_ head: ListNode?, _ k: Int) -> ListNode? {\n        \n    }\n}",
                    "__typename": "CodeSnippetNode"
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                {
                    "lang": "Go",
                    "langSlug": "golang",
                    "code": "/**\n * Definition for singly-linked list.\n * type ListNode struct {\n *     Val int\n *     Next *ListNode\n * }\n */\nfunc swapNodes(head *ListNode, k int) *ListNode {\n    \n}",
                    "__typename": "CodeSnippetNode"
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                {
                    "lang": "Scala",
                    "langSlug": "scala",
                    "code": "/**\n * Definition for singly-linked list.\n * class ListNode(_x: Int = 0, _next: ListNode = null) {\n *   var next: ListNode = _next\n *   var x: Int = _x\n * }\n */\nobject Solution {\n    def swapNodes(head: ListNode, k: Int): ListNode = {\n        \n    }\n}",
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                {
                    "lang": "Kotlin",
                    "langSlug": "kotlin",
                    "code": "/**\n * Example:\n * var li = ListNode(5)\n * var v = li.`val`\n * Definition for singly-linked list.\n * class ListNode(var `val`: Int) {\n *     var next: ListNode? = null\n * }\n */\nclass Solution {\n    fun swapNodes(head: ListNode?, k: Int): ListNode? {\n        \n    }\n}",
                    "__typename": "CodeSnippetNode"
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                {
                    "lang": "Rust",
                    "langSlug": "rust",
                    "code": "// Definition for singly-linked list.\n// #[derive(PartialEq, Eq, Clone, Debug)]\n// pub struct ListNode {\n//   pub val: i32,\n//   pub next: Option<Box<ListNode>>\n// }\n// \n// impl ListNode {\n//   #[inline]\n//   fn new(val: i32) -> Self {\n//     ListNode {\n//       next: None,\n//       val\n//     }\n//   }\n// }\nimpl Solution {\n    pub fn swap_nodes(head: Option<Box<ListNode>>, k: i32) -> Option<Box<ListNode>> {\n        \n    }\n}",
                    "__typename": "CodeSnippetNode"
                },
                {
                    "lang": "PHP",
                    "langSlug": "php",
                    "code": "/**\n * Definition for a singly-linked list.\n * class ListNode {\n *     public $val = 0;\n *     public $next = null;\n *     function __construct($val = 0, $next = null) {\n *         $this->val = $val;\n *         $this->next = $next;\n *     }\n * }\n */\nclass Solution {\n\n    /**\n     * @param ListNode $head\n     * @param Integer $k\n     * @return ListNode\n     */\n    function swapNodes($head, $k) {\n        \n    }\n}",
                    "__typename": "CodeSnippetNode"
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                    "lang": "TypeScript",
                    "langSlug": "typescript",
                    "code": "/**\n * Definition for singly-linked list.\n * class ListNode {\n *     val: number\n *     next: ListNode | null\n *     constructor(val?: number, next?: ListNode | null) {\n *         this.val = (val===undefined ? 0 : val)\n *         this.next = (next===undefined ? null : next)\n *     }\n * }\n */\n\nfunction swapNodes(head: ListNode | null, k: number): ListNode | null {\n\n};",
                    "__typename": "CodeSnippetNode"
                },
                {
                    "lang": "Racket",
                    "langSlug": "racket",
                    "code": "; Definition for singly-linked list:\n#|\n\n; val : integer?\n; next : (or/c list-node? #f)\n(struct list-node\n  (val next) #:mutable #:transparent)\n\n; constructor\n(define (make-list-node [val 0])\n  (list-node val #f))\n\n|#\n\n(define/contract (swap-nodes head k)\n  (-> (or/c list-node? #f) exact-integer? (or/c list-node? #f))\n\n  )",
                    "__typename": "CodeSnippetNode"
                },
                {
                    "lang": "Erlang",
                    "langSlug": "erlang",
                    "code": "%% Definition for singly-linked list.\n%%\n%% -record(list_node, {val = 0 :: integer(),\n%%                     next = null :: 'null' | #list_node{}}).\n\n-spec swap_nodes(Head :: #list_node{} | null, K :: integer()) -> #list_node{} | null.\nswap_nodes(Head, K) ->\n  .",
                    "__typename": "CodeSnippetNode"
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                {
                    "lang": "Elixir",
                    "langSlug": "elixir",
                    "code": "# Definition for singly-linked list.\n#\n# defmodule ListNode do\n#   @type t :: %__MODULE__{\n#           val: integer,\n#           next: ListNode.t() | nil\n#         }\n#   defstruct val: 0, next: nil\n# end\n\ndefmodule Solution do\n  @spec swap_nodes(head :: ListNode.t | nil, k :: integer) :: ListNode.t | nil\n  def swap_nodes(head, k) do\n\n  end\nend",
                    "__typename": "CodeSnippetNode"
                }
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            "hints": [
                "We can transform the linked list to an array this should ease things up",
                "After transforming the linked list to an array it becomes as easy as swapping two integers in an array then rebuilding the linked list"
            ],
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For the latest Python, please choose Python3 instead.</p>\"], \"c\": [\"C\", \"<p>Compiled with <code>gcc 8.2</code> using the gnu99 standard.</p>\\r\\n\\r\\n<p>Your code is compiled with level one optimization (<code>-O1</code>). <a href=\\\"https://github.com/google/sanitizers/wiki/AddressSanitizer\\\" target=\\\"_blank\\\">AddressSanitizer</a> is also enabled to help detect out-of-bounds and use-after-free bugs.</p>\\r\\n\\r\\n<p>Most standard library headers are already included automatically for your convenience.</p>\\r\\n\\r\\n<p>For hash table operations, you may use <a href=\\\"https://troydhanson.github.io/uthash/\\\" target=\\\"_blank\\\">uthash</a>. \\\"uthash.h\\\" is included by default. Below are some examples:</p>\\r\\n\\r\\n<p><b>1. 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