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<?php |
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declare(strict_types=1); |
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namespace Phpml\Math; |
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use ArrayIterator; |
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use IteratorAggregate; |
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class Set implements IteratorAggregate |
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{ |
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/** |
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* @var string[]|int[]|float[]|bool[] |
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*/ |
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private $elements = []; |
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/** |
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* @param string[]|int[]|float[]|bool[] $elements |
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*/ |
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public function __construct(array $elements = []) |
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{ |
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$this->elements = self::sanitize($elements); |
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} |
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/** |
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* Creates the union of A and B. |
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*/ |
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public static function union(self $a, self $b): self |
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{ |
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return new self(array_merge($a->toArray(), $b->toArray())); |
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} |
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/** |
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* Creates the intersection of A and B. |
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*/ |
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public static function intersection(self $a, self $b): self |
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{ |
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return new self(array_intersect($a->toArray(), $b->toArray())); |
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} |
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/** |
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* Creates the difference of A and B. |
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*/ |
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public static function difference(self $a, self $b): self |
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{ |
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return new self(array_diff($a->toArray(), $b->toArray())); |
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} |
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/** |
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* Creates the Cartesian product of A and B. |
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* |
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* @return Set[] |
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*/ |
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public static function cartesian(self $a, self $b): array |
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{ |
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$cartesian = []; |
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foreach ($a as $multiplier) { |
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foreach ($b as $multiplicand) { |
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$cartesian[] = new self(array_merge([$multiplicand], [$multiplier])); |
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} |
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} |
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return $cartesian; |
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} |
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/** |
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* Creates the power set of A. |
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* |
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* @return Set[] |
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*/ |
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public static function power(self $a): array |
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{ |
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$power = [new self()]; |
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foreach ($a as $multiplicand) { |
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foreach ($power as $multiplier) { |
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$power[] = new self(array_merge([$multiplicand], $multiplier->toArray())); |
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} |
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} |
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return $power; |
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} |
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/** |
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* @param string|int|float|bool $element |
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*/ |
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public function add($element): self |
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{ |
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return $this->addAll([$element]); |
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} |
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/** |
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* @param string[]|int[]|float[]|bool[] $elements |
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*/ |
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public function addAll(array $elements): self |
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{ |
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$this->elements = self::sanitize(array_merge($this->elements, $elements)); |
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return $this; |
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} |
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/** |
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* @param string|int|float $element |
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*/ |
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public function remove($element): self |
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{ |
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return $this->removeAll([$element]); |
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} |
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/** |
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* @param string[]|int[]|float[] $elements |
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*/ |
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public function removeAll(array $elements): self |
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{ |
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$this->elements = self::sanitize(array_diff($this->elements, $elements)); |
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return $this; |
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} |
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/** |
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* @param string|int|float $element |
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*/ |
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public function contains($element): bool |
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{ |
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return $this->containsAll([$element]); |
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} |
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/** |
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* @param string[]|int[]|float[] $elements |
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*/ |
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public function containsAll(array $elements): bool |
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{ |
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return count(array_diff($elements, $this->elements)) === 0; |
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} |
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/** |
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* @return string[]|int[]|float[]|bool[] |
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*/ |
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public function toArray(): array |
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{ |
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return $this->elements; |
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} |
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public function getIterator(): ArrayIterator |
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{ |
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return new ArrayIterator($this->elements); |
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} |
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public function isEmpty(): bool |
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{ |
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return $this->cardinality() === 0; |
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} |
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public function cardinality(): int |
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{ |
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return count($this->elements); |
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} |
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/** |
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* Removes duplicates and rewrites index. |
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* |
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* @param string[]|int[]|float[]|bool[] $elements |
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* |
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* @return string[]|int[]|float[]|bool[] |
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*/ |
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private static function sanitize(array $elements): array |
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{ |
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sort($elements, SORT_ASC); |
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return array_values(array_unique($elements, SORT_ASC)); |
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} |
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} |
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