Coding test for rightbalance

codetest-rb.php

<?php

/*
 Let’s say we are dealing with sending data over the internet, to make it simple, assume this plain text, in order to save some bandwidth we want to compress it, according to the following function:

compress(aaaaca) -> ax4ca
compress(aaaaaabbbcaaa) -> ax6bx3cax3
compress(mississippi) -> misx2isx2ipx2i
*/

function compress($string)
{
    $letters = str_split($string);
    $output = '';
    $letter_count = 1;
    foreach ($letters as $key => $letter) {
        $next_letter = $letters[$key+1];
        if ($letter == $next_letter) {
            $letter_count++;
        } else {
            if ($letter_count > 1) {
                $output .= $letter.'x'.$letter_count;
            } else {
                $output .= $letter;
            }
            $letter_count = 1;
        }
    }
    return $output;
}

$tests = array(
    [
        'test' => 'aaaaca',
        'expected' => 'ax4ca',
    ],
    [
        'test' => 'aaaaaabbbcaaa',
        'expected' => 'ax6bx3cax3',
    ],
    [
        'test' => 'mississippi',
        'expected' => 'misx2isx2ipx2i',
    ],
);

foreach ($tests as $key => $test) {
    $result = compress($test['test']);
    echo ($result == $test['expected']) ? "valid! compress(".$test['test'].") == ".$test['expected'] : "wrong! shoud be...".$test['expected'];
    echo '<br>';
    echo "result: $result";
    echo '<br><br>';
}