closest-amenity.php

<?php
namespace App;

/**
 * Brute force version. Will add optimised version later.
 */
class Block
{
    protected $blocks = [
        ['school'],
        ['gym'],
        ['gym', 'school'],
        ['school'],
        ['school','store']
    ];

    protected $needs = ['gym','school','store'];

    public function bestBlock()
    {
        $max = count($this->blocks);
        $indexes = [];
        
        foreach($this->blocks as $blockIndex => $blocks) {
            $indexes[$blockIndex] = [];
            foreach ($this->needs as $need) {
                foreach ($this->blocks as $innerIndex => $innerBlocks) {
                    if (in_array($need, $innerBlocks)) {
                        $temp = $blockIndex - $innerIndex;
                        $temp = $temp < 0 ? $temp * -1 : $temp;
                        $indexes[$blockIndex][$need] = $indexes[$blockIndex][$need] ?? $max;
                        $indexes[$blockIndex][$need] = $temp < $indexes[$blockIndex][$need] ? $temp : $indexes[$blockIndex][$need];
                    }
                }
            }
            $indexes[$blockIndex] = max($indexes[$blockIndex]);
        }

        return array_keys($indexes, min($indexes))[0];
    }
}