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<?php |
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declare(strict_types=1); |
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namespace leetcode; |
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class MinimumWindowSubstring |
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{ |
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public static function minWindow(string $s, string $t): string |
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{ |
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[$m, $n, $map, $win] = [strlen($s), strlen($t), [], []]; |
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if ($m === 0 || $n === 0) { |
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return ''; |
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} |
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for ($i = 0; $i < $n; $i++) { |
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$k = $t[$i]; |
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$map[$k] = ($map[$k] ?? 0) + 1; |
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} |
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$left = $right = $match = $start = 0; |
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$len = PHP_INT_MAX; |
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while ($right < $m) { |
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$c = $s[$right]; |
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$right++; |
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if (isset($map[$c])) { |
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$win[$c] = ($win[$c] ?? 0) + 1; |
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if ($win[$c] === $map[$c]) { |
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$match++; |
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} |
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} |
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while ($match === count($map)) { |
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if ($right - $left < $len) { |
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$start = $left; |
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$len = $right - $left; |
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} |
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$d = $s[$left]; |
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$left++; |
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if (isset($map[$d])) { |
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if ($win[$d] === $map[$d]) { |
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$match--; |
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} |
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$win[$d]--; |
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} |
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} |
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} |
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return $len === PHP_INT_MAX ? '' : substr($s, $start, $len); |
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} |
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public static function minWindow2(string $s, string $t): string |
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{ |
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[$m, $n, $map] = [strlen($s), strlen($t), []]; |
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if ($m === 0 || $n === 0) { |
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return ''; |
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} |
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for ($i = 0; $i < $n; $i++) { |
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$k = $t[$i]; |
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$map[$k] = ($map[$k] ?? 0) + 1; |
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} |
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$left = $right = $start = 0; |
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$len = PHP_INT_MAX; |
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while ($right < $m) { |
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$c = $s[$right]; |
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$right++; |
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if (isset($map[$c]) && $map[$c] > 0) { |
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$n--; |
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} |
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$map[$c] = ($map[$c] ?? 0) - 1; |
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while ($n === 0) { |
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if ($right - $left < $len) { |
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$len = $right - $left; |
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$start = $left; |
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} |
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$d = $s[$left]; |
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$left++; |
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$map[$d] = ($map[$d] ?? 0) + 1; |
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if ($map[$d] > 0) { |
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$n++; |
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} |
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} |
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} |
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return $len === PHP_INT_MAX ? '' : substr($s, $start, $len); |
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} |
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} |
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