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"question": {
"questionId": "2348",
"questionFrontendId": "2266",
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"title": "Count Number of Texts",
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"content": "<p>Alice is texting Bob using her phone. The <strong>mapping</strong> of digits to letters is shown in the figure below.</p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2022/03/15/1200px-telephone-keypad2svg.png\" style=\"width: 200px; height: 162px;\" />\n<p>In order to <strong>add</strong> a letter, Alice has to <strong>press</strong> the key of the corresponding digit <code>i</code> times, where <code>i</code> is the position of the letter in the key.</p>\n\n<ul>\n\t<li>For example, to add the letter <code>'s'</code>, Alice has to press <code>'7'</code> four times. Similarly, to add the letter <code>'k'</code>, Alice has to press <code>'5'</code> twice.</li>\n\t<li>Note that the digits <code>'0'</code> and <code>'1'</code> do not map to any letters, so Alice <strong>does not</strong> use them.</li>\n</ul>\n\n<p>However, due to an error in transmission, Bob did not receive Alice's text message but received a <strong>string of pressed keys</strong> instead.</p>\n\n<ul>\n\t<li>For example, when Alice sent the message <code>"bob"</code>, Bob received the string <code>"2266622"</code>.</li>\n</ul>\n\n<p>Given a string <code>pressedKeys</code> representing the string received by Bob, return <em>the <strong>total number of possible text messages</strong> Alice could have sent</em>.</p>\n\n<p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n\n<pre>\n<strong>Input:</strong> pressedKeys = "22233"\n<strong>Output:</strong> 8\n<strong>Explanation:</strong>\nThe possible text messages Alice could have sent are:\n"aaadd", "abdd", "badd", "cdd", "aaae", "abe", "bae", and "ce".\nSince there are 8 possible messages, we return 8.\n</pre>\n\n<p><strong>Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> pressedKeys = "222222222222222222222222222222222222"\n<strong>Output:</strong> 82876089\n<strong>Explanation:</strong>\nThere are 2082876103 possible text messages Alice could have sent.\nSince we need to return the answer modulo 10<sup>9</sup> + 7, we return 2082876103 % (10<sup>9</sup> + 7) = 82876089.\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>1 <= pressedKeys.length <= 10<sup>5</sup></code></li>\n\t<li><code>pressedKeys</code> only consists of digits from <code>'2'</code> - <code>'9'</code>.</li>\n</ul>\n",
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"exampleTestcases": "\"22233\"\n\"222222222222222222222222222222222222\"",
"categoryTitle": "Algorithms",
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"lang": "C++",
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"code": "class Solution {\npublic:\n int countTexts(string pressedKeys) {\n \n }\n};",
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"code": "class Solution {\n public int countTexts(String pressedKeys) {\n \n }\n}",
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"code": "class Solution(object):\n def countTexts(self, pressedKeys):\n \"\"\"\n :type pressedKeys: str\n :rtype: int\n \"\"\"\n ",
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"code": "class Solution:\n def countTexts(self, pressedKeys: str) -> int:\n ",
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"code": "\n\nint countTexts(char * pressedKeys){\n\n}",
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"code": "public class Solution {\n public int CountTexts(string pressedKeys) {\n \n }\n}",
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"lang": "JavaScript",
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"code": "/**\n * @param {string} pressedKeys\n * @return {number}\n */\nvar countTexts = function(pressedKeys) {\n \n};",
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"lang": "Ruby",
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"code": "# @param {String} pressed_keys\n# @return {Integer}\ndef count_texts(pressed_keys)\n \nend",
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"lang": "Swift",
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"code": "class Solution {\n func countTexts(_ pressedKeys: String) -> Int {\n \n }\n}",
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"lang": "Go",
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"code": "func countTexts(pressedKeys string) int {\n \n}",
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"code": "object Solution {\n def countTexts(pressedKeys: String): Int = {\n \n }\n}",
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"code": "class Solution {\n fun countTexts(pressedKeys: String): Int {\n \n }\n}",
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"code": "impl Solution {\n pub fn count_texts(pressed_keys: String) -> i32 {\n \n }\n}",
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"lang": "PHP",
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"code": "class Solution {\n\n /**\n * @param String $pressedKeys\n * @return Integer\n */\n function countTexts($pressedKeys) {\n \n }\n}",
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"lang": "TypeScript",
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"code": "function countTexts(pressedKeys: string): number {\n\n};",
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"lang": "Racket",
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"code": "(define/contract (count-texts pressedKeys)\n (-> string? exact-integer?)\n\n )",
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"lang": "Erlang",
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"code": "-spec count_texts(PressedKeys :: unicode:unicode_binary()) -> integer().\ncount_texts(PressedKeys) ->\n .",
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"code": "defmodule Solution do\n @spec count_texts(pressed_keys :: String.t) :: integer\n def count_texts(pressed_keys) do\n\n end\nend",
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"hints": [
"For a substring consisting of the same digit, how can we count the number of texts it could have originally represented?",
"How can dynamic programming help us calculate the required answer?"
],
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"status": null,
"sampleTestCase": "\"22233\"",
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