rector/vendor/sebastian/diff/src/TimeEfficientLongestCommonSubsequenceCalculator.php
Tomas Votruba f010267a7c Updated Rector to commit 6b69971dfc740a58aed918782d02710e42004e9d
6b69971dfc [NodeTypeCorrector] Directly use StringType on Intersection of strings on AccessoryNonEmptyStringTypeCorrector (#5933)
2024-06-01 09:25:16 +00:00

75 lines
2.3 KiB
PHP

<?php
declare (strict_types=1);
/*
* This file is part of sebastian/diff.
*
* (c) Sebastian Bergmann <sebastian@phpunit.de>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace RectorPrefix202406\SebastianBergmann\Diff;
use function array_reverse;
use function count;
use function max;
use SplFixedArray;
final class TimeEfficientLongestCommonSubsequenceCalculator implements LongestCommonSubsequenceCalculator
{
/**
* @inheritDoc
*/
public function calculate(array $from, array $to) : array
{
$common = [];
$fromLength = count($from);
$toLength = count($to);
$width = $fromLength + 1;
$matrix = new SplFixedArray($width * ($toLength + 1));
for ($i = 0; $i <= $fromLength; $i++) {
$matrix[$i] = 0;
}
for ($j = 0; $j <= $toLength; $j++) {
$matrix[$j * $width] = 0;
}
for ($i = 1; $i <= $fromLength; $i++) {
for ($j = 1; $j <= $toLength; $j++) {
$o = $j * $width + $i;
// don't use max() to avoid function call overhead
$firstOrLast = $from[$i - 1] === $to[$j - 1] ? $matrix[$o - $width - 1] + 1 : 0;
if ($matrix[$o - 1] > $matrix[$o - $width]) {
if ($firstOrLast > $matrix[$o - 1]) {
$matrix[$o] = $firstOrLast;
} else {
$matrix[$o] = $matrix[$o - 1];
}
} else {
if ($firstOrLast > $matrix[$o - $width]) {
$matrix[$o] = $firstOrLast;
} else {
$matrix[$o] = $matrix[$o - $width];
}
}
}
}
$i = $fromLength;
$j = $toLength;
while ($i > 0 && $j > 0) {
if ($from[$i - 1] === $to[$j - 1]) {
$common[] = $from[$i - 1];
$i--;
$j--;
} else {
$o = $j * $width + $i;
if ($matrix[$o - $width] > $matrix[$o - 1]) {
$j--;
} else {
$i--;
}
}
}
return array_reverse($common);
}
}