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Matrix Addition puzzle
<?php
/**
* Unit tests for Matrix Addition puzzle.
*
* Requirements: @see https://www.codewars.com/kata/matrix-addition
* Write a function that accepts two square matrices (N x N two dimensional arrays),
* and return the sum of the two.
* Both matrices being passed into the function will be of size N x N (square),
* containing only integers.
*
* How to sum two matrices:
* Take each cell [n][m] from the first matrix,
* and add it with the same [n][m] cell from the second matrix.
* This will be cell [n][m] of the solution matrix.
*
* @package Cata\Tests\Unit\MatrixAddition
* @author Caspar Green <caspar@iCasparWebDevelopment.com>
* @since 1.0.0
*/
declare(strict_types=1);
namespace Cata\Tests\Unit\MatrixAddition;
use Cata\MatrixAddition\MatrixAdder;
use PHPUnit\Framework\TestCase;
/**
* Class MatrixAdderTest
*
* @package Cata\Tests\Unit\MatrixAddition
* @since 1.0.0
*/
class MatrixAdderTest extends TestCase
{
/**
* A MatrixAdder instance.
*
* @var MatrixAdder
*/
private $matrixAdder;
/**
* Set up before each test.
*
* @since 1.0.0
*
* @return void
*/
protected function setUp()
{
$this->matrixAdder = new MatrixAdder();
}
/**
* Test addMatrices() should return the matrix sum for (1x1) addends.
*
* @since 1.0.0
*
* @return void
*/
public function testAddMatricesShouldReturnMatrixSumFor1x1(): void
{
$this->assertSame([[10]], $this->matrixAdder->addMatrices([[4]], [[6]]));
}
/**
* Test addMatrices() should return the matrix sum for (2x2) matrix.
*
* Once we have this, we have a working algorithm for (N x N).
*
* @since 1.0.0
*
* @return void
*/
public function testAddMatricesShouldReturnMatrixSumFor2x2(): void
{
$addend1 = [
[3, 5],
[4, 8],
];
$addend2 = [
[2, 7],
[6, 3],
];
$this->assertSame(
[
[5, 12],
[10, 11],
],
$this->matrixAdder->addMatrices($addend1, $addend2)
);
}
}
<?php
/**
* Matrix Adder puzzle class
*
* @package Cata\MatrixAddition
* @author Caspar Green <caspar@iCasparWebDevelopment.com>
* @since 1.0.0
*/
declare(strict_types=1);
namespace Cata\MatrixAddition;
/**
* Class MatrixAdder
*
* @package Cata\MatrixAddition
* @since 1.0.0
*/
class MatrixAdder
{
/**
* Add two matrices of integers.
*
* @param array $matrix1 First addend matrix.
* @param array $matrix2 Second addend matrix.
*
* @since 1.0.0
*
* @return array
*/
public function addMatrices(array $matrix1, array $matrix2): array
{
$sum = [];
foreach ($matrix1 as $row => $cols) {
foreach ($cols as $col => $value) {
$sum[$row][$col] = $matrix1[$row][$col] + $matrix2[$row][$col];
}
}
return $sum;
}
}
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