{ "data": { "question": { "questionId": "2275", "questionFrontendId": "2156", "boundTopicId": null, "title": "Find Substring With Given Hash Value", "titleSlug": "find-substring-with-given-hash-value", "content": "

The hash of a 0-indexed string s of length k, given integers p and m, is computed using the following function:

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Where val(s[i]) represents the index of s[i] in the alphabet from val('a') = 1 to val('z') = 26.

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You are given a string s and the integers power, modulo, k, and hashValue. Return sub, the first substring of s of length k such that hash(sub, power, modulo) == hashValue.

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The test cases will be generated such that an answer always exists.

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A substring is a contiguous non-empty sequence of characters within a string.

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Example 1:

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\nInput: s = "leetcode", power = 7, modulo = 20, k = 2, hashValue = 0\nOutput: "ee"\nExplanation: The hash of "ee" can be computed to be hash("ee", 7, 20) = (5 * 1 + 5 * 7) mod 20 = 40 mod 20 = 0. \n"ee" is the first substring of length 2 with hashValue 0. Hence, we return "ee".\n
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Example 2:

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\nInput: s = "fbxzaad", power = 31, modulo = 100, k = 3, hashValue = 32\nOutput: "fbx"\nExplanation: The hash of "fbx" can be computed to be hash("fbx", 31, 100) = (6 * 1 + 2 * 31 + 24 * 312) mod 100 = 23132 mod 100 = 32. \nThe hash of "bxz" can be computed to be hash("bxz", 31, 100) = (2 * 1 + 24 * 31 + 26 * 312) mod 100 = 25732 mod 100 = 32. \n"fbx" is the first substring of length 3 with hashValue 32. Hence, we return "fbx".\nNote that "bxz" also has a hash of 32 but it appears later than "fbx".\n
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Constraints:

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exact-integer? exact-integer? exact-integer? exact-integer? string?)\n )", "__typename": "CodeSnippetNode" }, { "lang": "Erlang", "langSlug": "erlang", "code": "-spec sub_str_hash(S :: unicode:unicode_binary(), Power :: integer(), Modulo :: integer(), K :: integer(), HashValue :: integer()) -> unicode:unicode_binary().\nsub_str_hash(S, Power, Modulo, K, HashValue) ->\n .", "__typename": "CodeSnippetNode" }, { "lang": "Elixir", "langSlug": "elixir", "code": "defmodule Solution do\n @spec sub_str_hash(s :: String.t, power :: integer, modulo :: integer, k :: integer, hash_value :: integer) :: String.t\n def sub_str_hash(s, power, modulo, k, hash_value) do\n \n end\nend", "__typename": "CodeSnippetNode" } ], "stats": "{\"totalAccepted\": \"12.3K\", \"totalSubmission\": \"53.7K\", \"totalAcceptedRaw\": 12321, \"totalSubmissionRaw\": 53736, \"acRate\": \"22.9%\"}", "hints": [ "How can we update the hash value efficiently while iterating instead of recalculating it each time?", "Use the rolling hash method." ], "solution": null, "status": null, "sampleTestCase": "\"leetcode\"\n7\n20\n2\n0", "metaData": "{\n \"name\": \"subStrHash\",\n \"params\": [\n {\n \"name\": \"s\",\n \"type\": \"string\"\n },\n {\n \"type\": \"integer\",\n \"name\": \"power\"\n },\n {\n \"type\": \"integer\",\n \"name\": \"modulo\"\n },\n {\n \"type\": \"integer\",\n \"name\": \"k\"\n },\n {\n \"type\": \"integer\",\n \"name\": \"hashValue\"\n }\n ],\n \"return\": {\n \"type\": \"string\"\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.

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

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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.

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

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

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

Python 2.7.12.

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

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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.

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

Compiled with gcc 8.2 using the gnu11 standard.

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

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

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

C# 10 with .NET 6 runtime

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

Node.js 16.13.2.

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

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lodash.js library is included by default.

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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

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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

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

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

Python 3.10.

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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

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Supports rand v0.6\\u00a0from crates.io

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

PHP 8.1.

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With bcmath module

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

TypeScript 5.1.6, Node.js 16.13.2.

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

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lodash.js library is included by default.

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

Run with Racket 8.3.

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Dart 2.17.3

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Your code will be run directly without compiling

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