{ "data": { "question": { "questionId": "2275", "questionFrontendId": "2156", "categoryTitle": "Algorithms", "boundTopicId": 1235011, "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:

\n\n\n\n

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

\n\n

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.

\n\n

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

\n\n

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

\n\n

 

\n

Example 1:

\n\n
\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
\n\n

Example 2:

\n\n
\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
\n\n

 

\n

Constraints:

\n\n\n", "translatedTitle": "查找给定哈希值的子串", "translatedContent": "

给定整数 p 和 m ，一个长度为 k 且下标从 0 开始的字符串 s 的哈希值按照如下函数计算：

\n\n\n\n

其中 val(s[i]) 表示 s[i] 在字母表中的下标，从 val('a') = 1 到 val('z') = 26 。

\n\n

给你一个字符串 s 和整数 power，modulo，k 和 hashValue 。请你返回 s 中 第一个 长度为 k 的 子串 sub ，满足 hash(sub, power, modulo) == hashValue 。

\n\n

测试数据保证一定 存在 至少一个这样的子串。

\n\n

子串 定义为一个字符串中连续非空字符组成的序列。

\n\n

 

\n\n

示例 1：

\n\n
输入：s = \"leetcode\", power = 7, modulo = 20, k = 2, hashValue = 0\n输出：\"ee\"\n解释：\"ee\" 的哈希值为 hash(\"ee\", 7, 20) = (5 * 1 + 5 * 7) mod 20 = 40 mod 20 = 0 。\n\"ee\" 是长度为 2 的第一个哈希值为 0 的子串，所以我们返回 \"ee\" 。\n
\n\n

示例 2：

\n\n
输入：s = \"fbxzaad\", power = 31, modulo = 100, k = 3, hashValue = 32\n输出：\"fbx\"\n解释：\"fbx\" 的哈希值为 hash(\"fbx\", 31, 100) = (6 * 1 + 2 * 31 + 24 * 312) mod 100 = 23132 mod 100 = 32 。\n\"bxz\" 的哈希值为 hash(\"bxz\", 31, 100) = (2 * 1 + 24 * 31 + 26 * 312) mod 100 = 25732 mod 100 = 32 。\n\"fbx\" 是长度为 3 的第一个哈希值为 32 的子串，所以我们返回 \"fbx\" 。\n注意，\"bxz\" 的哈希值也为 32 ，但是它在字符串中比 \"fbx\" 更晚出现。\n
\n\n

 

\n\n

提示：

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exact-integer? exact-integer? exact-integer? exact-integer? string?)\n\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\": \"4.5K\", \"totalSubmission\": \"18.8K\", \"totalAcceptedRaw\": 4525, \"totalSubmissionRaw\": 18783, \"acRate\": \"24.1%\"}", "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, "envInfo": "{\"cpp\":[\"C++\",\"

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