{ "data": { "question": { "questionId": "1885", "questionFrontendId": "1759", "boundTopicId": null, "title": "Count Number of Homogenous Substrings", "titleSlug": "count-number-of-homogenous-substrings", "content": "

Given a string s, return the number of homogenous substrings of s. Since the answer may be too large, return it modulo 109 + 7.

\n\n

A string is homogenous if all the characters of the string are the same.

\n\n

A substring is a contiguous sequence of characters within a string.

\n\n

 

\n

Example 1:

\n\n
\nInput: s = "abbcccaa"\nOutput: 13\nExplanation: The homogenous substrings are listed as below:\n"a"   appears 3 times.\n"aa"  appears 1 time.\n"b"   appears 2 times.\n"bb"  appears 1 time.\n"c"   appears 3 times.\n"cc"  appears 2 times.\n"ccc" appears 1 time.\n3 + 1 + 2 + 1 + 3 + 2 + 1 = 13.
\n\n

Example 2:

\n\n
\nInput: s = "xy"\nOutput: 2\nExplanation: The homogenous substrings are "x" and "y".
\n\n

Example 3:

\n\n
\nInput: s = "zzzzz"\nOutput: 15\n
\n\n

 

\n

Constraints:

\n\n\n", "translatedTitle": null, "translatedContent": null, "isPaidOnly": false, "difficulty": "Medium", "likes": 1431, "dislikes": 95, "isLiked": null, "similarQuestions": "[{\"title\": \"Consecutive Characters\", \"titleSlug\": \"consecutive-characters\", \"difficulty\": \"Easy\", \"translatedTitle\": null}, {\"title\": \"Number of Substrings With Only 1s\", \"titleSlug\": \"number-of-substrings-with-only-1s\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Sum of Subarray Ranges\", \"titleSlug\": \"sum-of-subarray-ranges\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Count the Number of Good Subarrays\", \"titleSlug\": \"count-the-number-of-good-subarrays\", \"difficulty\": \"Medium\", \"translatedTitle\": null}]", "exampleTestcases": "\"abbcccaa\"\n\"xy\"\n\"zzzzz\"", "categoryTitle": "Algorithms", "contributors": [], "topicTags": [ { "name": "Math", "slug": "math", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "String", "slug": "string", "translatedName": null, "__typename": "TopicTagNode" } ], "companyTagStats": null, "codeSnippets": [ { "lang": "C++", "langSlug": "cpp", "code": "class Solution {\npublic:\n int countHomogenous(string s) {\n \n }\n};", "__typename": "CodeSnippetNode" }, { "lang": "Java", "langSlug": "java", "code": "class Solution {\n public int countHomogenous(String s) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Python", "langSlug": "python", "code": "class Solution(object):\n def countHomogenous(self, s):\n \"\"\"\n :type s: str\n :rtype: int\n \"\"\"\n ", "__typename": "CodeSnippetNode" }, { "lang": "Python3", "langSlug": "python3", "code": "class Solution:\n def countHomogenous(self, s: str) -> int:\n ", "__typename": "CodeSnippetNode" }, { "lang": "C", "langSlug": "c", "code": "\n\nint countHomogenous(char * s){\n\n}", "__typename": "CodeSnippetNode" }, { "lang": "C#", "langSlug": "csharp", "code": "public class Solution {\n public int CountHomogenous(string s) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "JavaScript", "langSlug": "javascript", "code": "/**\n * @param {string} s\n * @return {number}\n */\nvar countHomogenous = function(s) {\n \n};", "__typename": "CodeSnippetNode" }, { "lang": "TypeScript", "langSlug": "typescript", "code": "function countHomogenous(s: string): number {\n\n};", "__typename": "CodeSnippetNode" }, { "lang": "PHP", "langSlug": "php", "code": "class Solution {\n\n /**\n * @param String $s\n * @return Integer\n */\n function countHomogenous($s) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Swift", "langSlug": "swift", "code": "class Solution {\n func countHomogenous(_ s: String) -> Int {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Kotlin", "langSlug": "kotlin", "code": "class Solution {\n fun countHomogenous(s: String): Int {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Go", "langSlug": "golang", "code": "func countHomogenous(s string) int {\n \n}", "__typename": "CodeSnippetNode" }, { "lang": "Ruby", "langSlug": "ruby", "code": "# @param {String} s\n# @return {Integer}\ndef count_homogenous(s)\n \nend", "__typename": "CodeSnippetNode" }, { "lang": "Scala", "langSlug": "scala", "code": "object Solution {\n def countHomogenous(s: String): Int = {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Rust", "langSlug": "rust", "code": "impl Solution {\n pub fn count_homogenous(s: String) -> i32 {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Racket", "langSlug": "racket", "code": "(define/contract (count-homogenous s)\n (-> string? exact-integer?)\n\n )", "__typename": "CodeSnippetNode" } ], "stats": "{\"totalAccepted\": \"105.2K\", \"totalSubmission\": \"181.3K\", \"totalAcceptedRaw\": 105224, \"totalSubmissionRaw\": 181263, \"acRate\": \"58.1%\"}", "hints": [ "A string of only 'a's of length k contains k + 1 choose 2 homogenous substrings.", "Split the string into substrings where each substring contains only one letter, and apply the formula on each substring's length." ], "solution": { "id": "2170", "canSeeDetail": true, "paidOnly": false, "hasVideoSolution": false, "paidOnlyVideo": true, "__typename": "ArticleNode" }, "status": null, "sampleTestCase": "\"abbcccaa\"", "metaData": "{\n \"name\": \"countHomogenous\",\n \"params\": [\n {\n \"name\": \"s\",\n \"type\": \"string\"\n }\n ],\n \"return\": {\n \"type\": \"integer\"\n }\n}", "judgerAvailable": true, "judgeType": "large", "mysqlSchemas": [], "enableRunCode": true, "enableTestMode": false, "enableDebugger": true, "envInfo": "{\"cpp\": [\"C++\", \"

Compiled with clang 11 using the latest C++ 20 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 gnu11 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

\"], \"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 5.3.0 version of datastructures-js/priority-queue and 4.2.1 version of 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 1.21

\\r\\n

Support https://godoc.org/github.com/emirpasic/gods@v1.18.1 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 1.9.0.

\"], \"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 5.1.6, Node.js 16.13.2.

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

Your code is run with --harmony flag, enabling new ES2022 features.

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

lodash.js library is included by default.

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

Run with Racket 8.3.

\"]}", "libraryUrl": null, "adminUrl": null, "challengeQuestion": { "id": "1546", "date": "2023-11-09", "incompleteChallengeCount": 0, "streakCount": 0, "type": "DAILY", "__typename": "ChallengeQuestionNode" }, "__typename": "QuestionNode" } } }