{ "data": { "question": { "questionId": "138", "questionFrontendId": "138", "categoryTitle": "Algorithms", "boundTopicId": 1298, "title": "Copy List with Random Pointer", "titleSlug": "copy-list-with-random-pointer", "content": "

A linked list of length n is given such that each node contains an additional random pointer, which could point to any node in the list, or null.

\n\n

Construct a deep copy of the list. The deep copy should consist of exactly n brand new nodes, where each new node has its value set to the value of its corresponding original node. Both the next and random pointer of the new nodes should point to new nodes in the copied list such that the pointers in the original list and copied list represent the same list state. None of the pointers in the new list should point to nodes in the original list.

\n\n

For example, if there are two nodes X and Y in the original list, where X.random --> Y, then for the corresponding two nodes x and y in the copied list, x.random --> y.

\n\n

Return the head of the copied linked list.

\n\n

The linked list is represented in the input/output as a list of n nodes. Each node is represented as a pair of [val, random_index] where:

\n\n\n\n

Your code will only be given the head of the original linked list.

\n\n

 

\n

Example 1:

\n\"\"\n
\nInput: head = [[7,null],[13,0],[11,4],[10,2],[1,0]]\nOutput: [[7,null],[13,0],[11,4],[10,2],[1,0]]\n
\n\n

Example 2:

\n\"\"\n
\nInput: head = [[1,1],[2,1]]\nOutput: [[1,1],[2,1]]\n
\n\n

Example 3:

\n\n

\"\"

\n\n
\nInput: head = [[3,null],[3,0],[3,null]]\nOutput: [[3,null],[3,0],[3,null]]\n
\n\n

 

\n

Constraints:

\n\n\n", "translatedTitle": "复制带随机指针的链表", "translatedContent": "

给你一个长度为 n 的链表，每个节点包含一个额外增加的随机指针 random ，该指针可以指向链表中的任何节点或空节点。

\n\n

构造这个链表的 深拷贝。 深拷贝应该正好由 n 个 全新 节点组成，其中每个新节点的值都设为其对应的原节点的值。新节点的 next 指针和 random 指针也都应指向复制链表中的新节点，并使原链表和复制链表中的这些指针能够表示相同的链表状态。复制链表中的指针都不应指向原链表中的节点 。

\n\n

例如，如果原链表中有 X 和 Y 两个节点，其中 X.random --> Y 。那么在复制链表中对应的两个节点 x 和 y ，同样有 x.random --> y 。

\n\n

返回复制链表的头节点。

\n\n

用一个由 n 个节点组成的链表来表示输入/输出中的链表。每个节点用一个 [val, random_index] 表示：

\n\n\n\n

你的代码 只 接受原链表的头节点 head 作为传入参数。

\n\n

 

\n\n

示例 1：

\n\n

\"\"

\n\n
\n输入：head = [[7,null],[13,0],[11,4],[10,2],[1,0]]\n输出：[[7,null],[13,0],[11,4],[10,2],[1,0]]\n
\n\n

示例 2：

\n\n

\"\"

\n\n
\n输入：head = [[1,1],[2,1]]\n输出：[[1,1],[2,1]]\n
\n\n

示例 3：

\n\n

\"\"

\n\n
\n输入：head = [[3,null],[3,0],[3,null]]\n输出：[[3,null],[3,0],[3,null]]\n
\n\n

 

\n\n

提示：

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{\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Go", "langSlug": "golang", "code": "/**\n * Definition for a Node.\n * type Node struct {\n * Val int\n * Next *Node\n * Random *Node\n * }\n */\n\nfunc copyRandomList(head *Node) *Node {\n \n}", "__typename": "CodeSnippetNode" }, { "lang": "Scala", "langSlug": "scala", "code": "/**\n * Definition for a Node.\n * class Node(var _value: Int) {\n * var value: Int = _value\n * var next: Node = null\n * var random: Node = null\n * }\n */\n\nobject Solution {\n def copyRandomList(head: Node): Node = {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Kotlin", "langSlug": "kotlin", "code": "/**\n * Example:\n * var ti = Node(5)\n * var v = ti.`val`\n * Definition for a Node.\n * class Node(var `val`: Int) {\n * var next: Node? = null\n * var random: Node? = null\n * }\n */\n\nclass Solution {\n fun copyRandomList(node: Node?): Node? {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "PHP", "langSlug": "php", "code": "/**\n * Definition for a Node.\n * class Node {\n * public $val = null;\n * public $next = null;\n * public $random = null;\n * function __construct($val = 0) {\n * $this->val = $val;\n * $this->next = null;\n * $this->random = null;\n * }\n * }\n */\n\nclass Solution {\n /**\n * @param Node $head\n * @return Node\n */\n function copyRandomList($head) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "TypeScript", "langSlug": "typescript", "code": "/**\n * Definition for Node.\n * class Node {\n * val: number\n * next: Node | null\n * random: Node | null\n * constructor(val?: number, next?: Node, random?: Node) {\n * this.val = (val===undefined ? 0 : val)\n * this.next = (next===undefined ? null : next)\n * this.random = (random===undefined ? null : random)\n * }\n * }\n */\n\nfunction copyRandomList(head: Node | null): Node | null {\n \n};", "__typename": "CodeSnippetNode" } ], "stats": "{\"totalAccepted\": \"145.1K\", \"totalSubmission\": \"216.8K\", \"totalAcceptedRaw\": 145110, \"totalSubmissionRaw\": 216832, \"acRate\": \"66.9%\"}", "hints": [ "Just iterate the linked list and create copies of the nodes on the go. Since a node can be referenced from multiple nodes due to the random pointers, make sure you are not making multiple copies of the same node.", "You may want to use extra space to keep old node ---> new node mapping to prevent creating multiples copies of same node.", "We can avoid using extra space for old node ---> new node mapping, by tweaking the original linked list. Simply interweave the nodes of the old and copied list. \r\nFor e.g.\r\n
\r\nOld List: A --> B --> C --> D\r\nInterWeaved List: A --> A' --> B --> B' --> C --> C' --> D --> D'\r\n
", "The interweaving is done using next pointers and we can make use of interweaved structure to get the correct reference nodes for random pointers." ], "solution": null, "status": null, "sampleTestCase": "[[7,null],[13,0],[11,4],[10,2],[1,0]]", "metaData": "{\n \"name\": \"copyRandomList\",\n \"params\": [\n {\n \"name\": \"head\",\n \"type\": \"ListNode\"\n }\n ],\n \"return\": {\n \"type\": \"ListNode\"\n },\n \"languages\": [\n \"cpp\",\n \"java\",\n \"python\",\n \"csharp\",\n \"javascript\",\n \"python3\",\n \"golang\",\n \"swift\",\n \"kotlin\",\n \"ruby\",\n \"c\",\n \"scala\",\n \"php\",\n \"typescript\"\n ],\n \"manual\": true\n}", "judgerAvailable": true, "judgeType": "large", "mysqlSchemas": [], "enableRunCode": true, "envInfo": "{\"cpp\":[\"C++\",\"

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