{ "data": { "question": { "questionId": "2299", "questionFrontendId": "2181", "boundTopicId": null, "title": "Merge Nodes in Between Zeros", "titleSlug": "merge-nodes-in-between-zeros", "content": "

You are given the head of a linked list, which contains a series of integers separated by 0's. The beginning and end of the linked list will have Node.val == 0.

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For every two consecutive 0's, merge all the nodes lying in between them into a single node whose value is the sum of all the merged nodes. The modified list should not contain any 0's.

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Return the head of the modified linked list.

\n\n

 

\n

Example 1:

\n\"\"\n
\nInput: head = [0,3,1,0,4,5,2,0]\nOutput: [4,11]\nExplanation: \nThe above figure represents the given linked list. The modified list contains\n- The sum of the nodes marked in green: 3 + 1 = 4.\n- The sum of the nodes marked in red: 4 + 5 + 2 = 11.\n
\n\n

Example 2:

\n\"\"\n
\nInput: head = [0,1,0,3,0,2,2,0]\nOutput: [1,3,4]\nExplanation: \nThe above figure represents the given linked list. The modified list contains\n- The sum of the nodes marked in green: 1 = 1.\n- The sum of the nodes marked in red: 3 = 3.\n- The sum of the nodes marked in yellow: 2 + 2 = 4.\n
\n\n

 

\n

Constraints:

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0 : val)\n * this.next = (next===undefined ? null : next)\n * }\n */\n/**\n * @param {ListNode} head\n * @return {ListNode}\n */\nvar mergeNodes = function(head) {\n \n};", "__typename": "CodeSnippetNode" }, { "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# @return {ListNode}\ndef merge_nodes(head)\n \nend", "__typename": "CodeSnippetNode" }, { "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 mergeNodes(_ head: ListNode?) -> ListNode? {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Go", "langSlug": "golang", "code": "/**\n * Definition for singly-linked list.\n * type ListNode struct {\n * Val int\n * Next *ListNode\n * }\n */\nfunc mergeNodes(head *ListNode) *ListNode {\n \n}", "__typename": "CodeSnippetNode" }, { "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 mergeNodes(head: ListNode): ListNode = {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "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 mergeNodes(head: ListNode?): ListNode? {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "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>\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 merge_nodes(head: Option>) -> Option> {\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 $head\n * @return ListNode\n */\n function mergeNodes($head) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "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 mergeNodes(head: ListNode | null): 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 (merge-nodes head)\n (-> (or/c list-node? #f) (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 merge_nodes(Head :: #list_node{} | null) -> #list_node{} | null.\nmerge_nodes(Head) ->\n .", "__typename": "CodeSnippetNode" }, { "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 merge_nodes(head :: ListNode.t | nil) :: ListNode.t | nil\n def merge_nodes(head) do\n\n end\nend", "__typename": "CodeSnippetNode" } ], "stats": "{\"totalAccepted\": \"24.2K\", \"totalSubmission\": \"27.7K\", \"totalAcceptedRaw\": 24229, \"totalSubmissionRaw\": 27734, \"acRate\": \"87.4%\"}", "hints": [ "How can you use two pointers to modify the original list into the new list?", "Have a pointer traverse the entire linked list, while another pointer looks at a node that is currently being modified.", "Keep on summing the values of the nodes between the traversal pointer and the modifying pointer until the former comes across a ‘0’. In that case, the modifying pointer is incremented to modify the next node.", "Do not forget to have the next pointer of the final node of the modified list point to null." ], "solution": null, "status": null, "sampleTestCase": "[0,3,1,0,4,5,2,0]", "metaData": "{\n \"name\": \"mergeNodes\",\n \"params\": [\n {\n \"name\": \"head\",\n \"type\": \"ListNode\"\n }\n ],\n \"return\": {\n \"type\": \"ListNode\"\n }\n}", "judgerAvailable": true, "judgeType": "large", "mysqlSchemas": [], "enableRunCode": true, "enableTestMode": false, "enableDebugger": true, "envInfo": "{\"cpp\": [\"C++\", \"

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For Map/TreeMap data structure, you may use sortedcontainers library.

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Note that Python 2.7 will not be maintained past 2020. For the latest Python, please choose Python3 instead.

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Your code is compiled with level one optimization (-O1). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.

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