advent_of_code_2019/day_10/functions.php

<?php


/**
 * @param array $array
 * @return array|bool
 */
function array_flatten(array $array) {
    return iterator_to_array(array_flatten_iterator($array), false);
}

/**
 * @param array $array
 * @return Generator
 */
function array_flatten_iterator(array $array) {
    foreach ($array as $value) {
        if (is_array($value)) {
            yield from array_flatten_iterator($value);
        } else {
            yield $value;
        }
    }
}

/**
 * @param int $x1
 * @param int $y1
 * @param int $x2
 * @param int $y2
 *
 * @return array
 */
function getPointsBetween(int $x1, int $y1, int $x2, int $y2)
{
    $dx = $x2-$x1;
    $dy = $y2-$y1;
    $max = max(abs($dx), abs($dy));
    for($t = 0; $t<=$max; $t++) {
        $points[] = sprintf('%s,%s', $x1+($t*$dx)/$max, $y1+($t*$dy)/$max);
    }

    return $points;
}