{ "data": { "question": { "questionId": "301", "questionFrontendId": "301", "boundTopicId": null, "title": "Remove Invalid Parentheses", "titleSlug": "remove-invalid-parentheses", "content": "

Given a string s that contains parentheses and letters, remove the minimum number of invalid parentheses to make the input string valid.

\n\n

Return all the possible results. You may return the answer in any order.

\n\n

 

\n

Example 1:

\n\n
\nInput: s = "()())()"\nOutput: ["(())()","()()()"]\n
\n\n

Example 2:

\n\n
\nInput: s = "(a)())()"\nOutput: ["(a())()","(a)()()"]\n
\n\n

Example 3:

\n\n
\nInput: s = ")("\nOutput: [""]\n
\n\n

 

\n

Constraints:

\n\n\n", "translatedTitle": null, "translatedContent": null, "isPaidOnly": false, "difficulty": "Hard", "likes": 4524, "dislikes": 230, "isLiked": null, "similarQuestions": "[{\"title\": \"Valid Parentheses\", \"titleSlug\": \"valid-parentheses\", \"difficulty\": \"Easy\", \"translatedTitle\": null}, {\"title\": \"Minimum Number of Swaps to Make the String Balanced\", \"titleSlug\": \"minimum-number-of-swaps-to-make-the-string-balanced\", \"difficulty\": \"Medium\", \"translatedTitle\": null}]", "exampleTestcases": "\"()())()\"\n\"(a)())()\"\n\")(\"", "categoryTitle": "Algorithms", "contributors": [], "topicTags": [ { "name": "String", "slug": "string", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Backtracking", "slug": "backtracking", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Breadth-First Search", "slug": "breadth-first-search", "translatedName": null, "__typename": "TopicTagNode" } ], "companyTagStats": null, "codeSnippets": [ { "lang": "C++", "langSlug": "cpp", "code": "class Solution {\npublic:\n vector removeInvalidParentheses(string s) {\n \n }\n};", "__typename": "CodeSnippetNode" }, { "lang": "Java", "langSlug": "java", "code": "class Solution {\n public List removeInvalidParentheses(String s) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Python", "langSlug": "python", "code": "class Solution(object):\n def removeInvalidParentheses(self, s):\n \"\"\"\n :type s: str\n :rtype: List[str]\n \"\"\"\n ", "__typename": "CodeSnippetNode" }, { "lang": "Python3", "langSlug": "python3", "code": "class Solution:\n def removeInvalidParentheses(self, s: str) -> List[str]:\n ", "__typename": "CodeSnippetNode" }, { "lang": "C", "langSlug": "c", "code": "\n\n/**\n * Note: The returned array must be malloced, assume caller calls free().\n */\nchar ** removeInvalidParentheses(char * s, int* returnSize){\n\n}", "__typename": "CodeSnippetNode" }, { "lang": "C#", "langSlug": "csharp", "code": "public class Solution {\n public IList RemoveInvalidParentheses(string s) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "JavaScript", "langSlug": "javascript", "code": "/**\n * @param {string} s\n * @return {string[]}\n */\nvar removeInvalidParentheses = function(s) {\n \n};", "__typename": "CodeSnippetNode" }, { "lang": "Ruby", "langSlug": "ruby", "code": "# @param {String} s\n# @return {String[]}\ndef remove_invalid_parentheses(s)\n \nend", "__typename": "CodeSnippetNode" }, { "lang": "Swift", "langSlug": "swift", "code": "class Solution {\n func removeInvalidParentheses(_ s: String) -> [String] {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Go", "langSlug": "golang", "code": "func removeInvalidParentheses(s string) []string {\n \n}", "__typename": "CodeSnippetNode" }, { "lang": "Scala", "langSlug": "scala", "code": "object Solution {\n def removeInvalidParentheses(s: String): List[String] = {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Kotlin", "langSlug": "kotlin", "code": "class Solution {\n fun removeInvalidParentheses(s: String): List {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Rust", "langSlug": "rust", "code": "impl Solution {\n pub fn remove_invalid_parentheses(s: String) -> Vec {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "PHP", "langSlug": "php", "code": "class Solution {\n\n /**\n * @param String $s\n * @return String[]\n */\n function removeInvalidParentheses($s) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "TypeScript", "langSlug": "typescript", "code": "function removeInvalidParentheses(s: string): string[] {\n\n};", "__typename": "CodeSnippetNode" }, { "lang": "Racket", "langSlug": "racket", "code": "(define/contract (remove-invalid-parentheses s)\n (-> string? (listof string?))\n\n )", "__typename": "CodeSnippetNode" }, { "lang": "Erlang", "langSlug": "erlang", "code": "-spec remove_invalid_parentheses(S :: unicode:unicode_binary()) -> [unicode:unicode_binary()].\nremove_invalid_parentheses(S) ->\n .", "__typename": "CodeSnippetNode" }, { "lang": "Elixir", "langSlug": "elixir", "code": "defmodule Solution do\n @spec remove_invalid_parentheses(s :: String.t) :: [String.t]\n def remove_invalid_parentheses(s) do\n\n end\nend", "__typename": "CodeSnippetNode" } ], "stats": "{\"totalAccepted\": \"340.5K\", \"totalSubmission\": \"728.4K\", \"totalAcceptedRaw\": 340517, \"totalSubmissionRaw\": 728405, \"acRate\": \"46.7%\"}", "hints": [ "Since we don't know which of the brackets can possibly be removed, we try out all the options!", "We can use recursion to try out all possibilities for the given expression. For each of the brackets, we have 2 options:\r\n\r\n
    \r\n
  1. We keep the bracket and add it to the expression that we are building on the fly during recursion.
    2. \r\n
  2. OR, we can discard the bracket and move on.\r\n
", "The one thing all these valid expressions have in common is that they will all be of the same length i.e. as compared to the original expression, all of these expressions will have the same number of characters removed. \r\n\r\nCan we somehow find the number of misplaced parentheses and use it in our solution?", "For every left parenthesis, we should have a corresponding right parenthesis. We can make use of two counters which keep track of misplaced left and right parenthesis and in one iteration we can find out these two values. \r\n\r\n
\r\n0 1 2 3 4 5 6 7\r\n( ) ) ) ( ( ( )  \r\ni = 0, left = 1, right = 0\r\ni = 1, left = 0, right = 0\r\ni = 2, left = 0, right = 1\r\ni = 3, left = 0, right = 2\r\ni = 4, left = 1, right = 2\r\ni = 5, left = 2, right = 2\r\ni = 6, left = 3, right = 2\r\ni = 7, left = 2, right = 2\r\n
\r\n\r\nWe have 2 misplaced left and 2 misplaced right parentheses.", "We found out that the exact number of left and right parenthesis that has to be removed to get a valid expression. So, e.g. in a 1000 parentheses string, if there are 2 misplaced left and 2 misplaced right parentheses, after we are done discarding 2 left and 2 right parentheses, we will have only one option per remaining character in the expression i.e. to consider them. We can't discard them." ], "solution": { "id": "577", "canSeeDetail": true, "paidOnly": false, "hasVideoSolution": false, "paidOnlyVideo": true, "__typename": "ArticleNode" }, "status": null, "sampleTestCase": "\"()())()\"", "metaData": "{\r\n \"name\":\"removeInvalidParentheses\",\r\n \"params\":[\r\n {\r\n \"name\":\"s\",\r\n \"type\":\"string\"\r\n }\r\n ],\r\n \"return\":{\r\n \"type\":\"list\"\r\n }\r\n}", "judgerAvailable": true, "judgeType": "large", "mysqlSchemas": [], "enableRunCode": true, "enableTestMode": false, "enableDebugger": true, "envInfo": "{\"cpp\": [\"C++\", \"

Compiled with clang 11 using the latest C++ 17 standard.

\\r\\n\\r\\n

Your code is compiled with level two optimization (-O2). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.

\\r\\n\\r\\n

Most standard library headers are already included automatically for your convenience.

\"], \"java\": [\"Java\", \"

OpenJDK 17 . Java 8 features such as lambda expressions and stream API can be used.

\\r\\n\\r\\n

Most standard library headers are already included automatically for your convenience.

\\r\\n

Includes Pair class from https://docs.oracle.com/javase/8/javafx/api/javafx/util/Pair.html.

\"], \"python\": [\"Python\", \"

Python 2.7.12.

\\r\\n\\r\\n

Most libraries are already imported automatically for your convenience, such as array, bisect, collections. If you need more libraries, you can import it yourself.

\\r\\n\\r\\n

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

\\r\\n\\r\\n

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

\"], \"c\": [\"C\", \"

Compiled with gcc 8.2 using the gnu99 standard.

\\r\\n\\r\\n

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

\\r\\n\\r\\n

Most standard library headers are already included automatically for your convenience.

\\r\\n\\r\\n

For hash table operations, you may use uthash. \\\"uthash.h\\\" is included by default. Below are some examples:

\\r\\n\\r\\n

1. Adding an item to a hash.\\r\\n

\\r\\nstruct hash_entry {\\r\\n    int id;            /* we'll use this field as the key */\\r\\n    char name[10];\\r\\n    UT_hash_handle hh; /* makes this structure hashable */\\r\\n};\\r\\n\\r\\nstruct hash_entry *users = NULL;\\r\\n\\r\\nvoid add_user(struct hash_entry *s) {\\r\\n    HASH_ADD_INT(users, id, s);\\r\\n}\\r\\n
\\r\\n

\\r\\n\\r\\n

2. Looking up an item in a hash:\\r\\n

\\r\\nstruct hash_entry *find_user(int user_id) {\\r\\n    struct hash_entry *s;\\r\\n    HASH_FIND_INT(users, &user_id, s);\\r\\n    return s;\\r\\n}\\r\\n
\\r\\n

\\r\\n\\r\\n

3. Deleting an item in a hash:\\r\\n

\\r\\nvoid delete_user(struct hash_entry *user) {\\r\\n    HASH_DEL(users, user);  \\r\\n}\\r\\n
\\r\\n

\"], \"csharp\": [\"C#\", \"

C# 10 with .NET 6 runtime

\\r\\n\\r\\n

Your code is compiled with debug flag enabled (/debug).

\"], \"javascript\": [\"JavaScript\", \"

Node.js 16.13.2.

\\r\\n\\r\\n

Your code is run with --harmony flag, enabling new ES6 features.

\\r\\n\\r\\n

lodash.js library is included by default.

\\r\\n\\r\\n

For Priority Queue / Queue data structures, you may use datastructures-js/priority-queue and datastructures-js/queue.

\"], \"ruby\": [\"Ruby\", \"

Ruby 3.1

\\r\\n\\r\\n

Some common data structure implementations are provided in the Algorithms module: https://www.rubydoc.info/github/kanwei/algorithms/Algorithms

\"], \"swift\": [\"Swift\", \"

Swift 5.5.2.

\"], \"golang\": [\"Go\", \"

Go 1.17.6.

\\r\\n\\r\\n

Support https://godoc.org/github.com/emirpasic/gods library.

\"], \"python3\": [\"Python3\", \"

Python 3.10.

\\r\\n\\r\\n

Most libraries are already imported automatically for your convenience, such as array, bisect, collections. If you need more libraries, you can import it yourself.

\\r\\n\\r\\n

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

\"], \"scala\": [\"Scala\", \"

Scala 2.13.7.

\"], \"kotlin\": [\"Kotlin\", \"

Kotlin 1.3.10.

\"], \"rust\": [\"Rust\", \"

Rust 1.58.1

\\r\\n\\r\\n

Supports rand v0.6\\u00a0from crates.io

\"], \"php\": [\"PHP\", \"

PHP 8.1.

\\r\\n

With bcmath module

\"], \"typescript\": [\"Typescript\", \"

TypeScript 4.5.4, Node.js 16.13.2.

\\r\\n\\r\\n

Your code is run with --harmony flag, enabling new ES2020 features.

\\r\\n\\r\\n

lodash.js library is included by default.

\"], \"racket\": [\"Racket\", \"

Run with Racket 8.3.

\"], \"erlang\": [\"Erlang\", \"Erlang/OTP 24.2\"], \"elixir\": [\"Elixir\", \"Elixir 1.13.0 with Erlang/OTP 24.2\"]}", "libraryUrl": null, "adminUrl": null, "challengeQuestion": null, "__typename": "QuestionNode" } } }