php array rotation

Question

Of these two integer arrays, how do I determine if the second array is a rotated version of the first array and which php function is required?

Example: Original array A=[1,2,3,4,5,6,7,8] Rotate array B=[6,7,8,1,2,3,4,5]

In this example, all numbers in array A are rotated 5 positions to the right.

Answer 1

There is no built-in function, but you can rotate each position and compare whether it is correct.

$isRotated = function (array $original, array $maybeRotated): bool {
    $originalCount     = count($original);
    $maybeRotatedCount = count($maybeRotated);
    if ($originalCount !== $maybeRotatedCount || $original === $maybeRotated) {
        return false;
    }

    for ($i = 0; $i < $originalCount; $i++) {
        $original[] = array_shift($original);
        if ($original === $maybeRotated) {
            return true;
        }
    }

    return false;
};

echo $isRotated([1, 2, 3, 4, 5, 6, 7, 8], [6, 7, 8, 1, 2, 3, 4, 5]) ? 'true' : 'false', PHP_EOL;
echo $isRotated([1, 2, 3, 4, 5, 6, 7, 8], [1, 2, 3, 4, 5, 6, 7, 8]) ? 'true' : 'false', PHP_EOL;
echo $isRotated([1, 2, 3, 4, 5, 6, 7, 8], [2, 3, 4, 5, 6, 7, 8, 1]) ? 'true' : 'false', PHP_EOL;

Output

true
false
true