Dokaku16.php

<?php

declare(strict_types=1);

namespace Nagoyaphp\Dokaku16;

class Dokaku16
{
    public $ok;
    public $numbers;
    public $height;
    public $width;
    public function run(string $input) : string
    {
        $this->setNumbers($input);
        for ($i=0;$i<$this->width*$this->height;$i++) {
            $this->findRoutes();
        }

        return $this->getResults();
    }

    public function getResults() {
        $output = '';
        for ($i=0;$i<$this->width*$this->height;$i++) {
            $output .= $this->returnAsteriskOrNumber($i);
            if ($i % $this->width == $this->width -1) { // 行の最後に / を入れる
                $output .= '/';
            }
        }
        $output = trim($output, '/'); // 一番最後の / は削る
        return $output;
    }
    public function returnAsteriskOrNumber($position) {
        if ($this->ok[$position]) {
            return '*';
        } else {
            return $this->numbers[$position];
        }
    }
    public function setNumbers($input) {
        // 幅は、入力の最初の / の位置
        $this->width = strpos($input, '/');
        // 高さは、/ の数 +1
        $this->height = 1 + substr_count($input, '/');

        $input = str_replace('/', '', $input);
        $this->numbers = str_split($input);

        $this->ok = [];
        for ($i=0;$i<$this->width*$this->height;$i++) {
            $this->ok[] = 0;
            $this->ok[2] = 1; // 中央の上は3番目
        }

    }

    public function findRoutes() {
        for ($i=0;$i<$this->width*$this->height;$i++) {
            $adjacents = [];
            if ($i % $this->width != 0) { // left
                $adjacents[] = $i-1;
            }
            if ($i % $this->width != $this->width-1) { // right
                $adjacents[] = $i+1;
            }
            if ($i >= $this->height) { // up
                $adjacents[] = $i - $this->height;
            }
            if ($i < ($this->width -1) * $this->height) { // down
                $adjacents[] = $i + $this->height;
            }
            foreach ($adjacents as $adjacent) {
                $this->checkOk($i,$adjacent);
            }
        }
    }
    public function checkOk($val1, $val2) {
        if ($this->isOk($val2) && $this->diff($val1, $val2)) {
            $this->ok[$val1] = 1;
        }
    }
    public function isOk($val) {
        return $this->ok[$val];
    }
    public function diff($val1, $val2) {
        if ($this->numbers[$val1] == $this->numbers[$val2]) {
            return true;
        } elseif($this->numbers[$val1] == (1 + $this->numbers[$val2])) {
            return true;
        } elseif ($this->numbers[$val1] == (-1 + $this->numbers[$val2])) {
            return true;
        } else {
            return false;
        }
    }
}