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49 lines
1.0 KiB
49 lines
1.0 KiB
<?php
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class Solution
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{
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const letters = [
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2 => ['a','b','c'],
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3 => ['d','e','f'],
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4 => ['g','h','i'],
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5 => ['j','k','l'],
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6 => ['m','n','o'],
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7 => ['p','q','r','s'],
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8 => ['t','u','v'],
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9 => ['w','x','y','z']
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];
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/**
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* @param mixed $digits
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* @access public
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* @return array
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*/
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public static function letterCombinations($digits): array
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{
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if ($digits === '') {
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return [];
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}
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$lookupResult = [];
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$x = 0;
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while (count($lookupResult) === 0) {
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$lookupResult = self::letters[$digits[$x]] ?? [];
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$x++;
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}
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for ($i = 1; $i < strlen($digits); $i++) {
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$temp = [];
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foreach (self::letters[$digits[$i]] as $char) {
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foreach ($lookupResult as $r) {
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$temp[] = $r . $char;
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}
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}
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$lookupResult = $temp;
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}
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return $lookupResult;
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}
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}
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