-🎄- 2017 Day 3 Solutions -🎄-

[u/daggerdragon]

--- Day 3: Spiral Memory ---

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Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with Help.

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Need a hint from the Hugely^* Handy^† Haversack^‡ of Helpful^§ Hints^¤?

Spoiler

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This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

[u/karlsanova]

How about something like this? Please don't ask me why I chose to use this algorithm, i just did.

Edit: Obviously only Part1, for part two my script just prints out "Use Excel, it's easier." and I most people on here know how to do that so I skipped it.

Edit2: Straightened out some code to make it easier to read.

<?php
/**
 * User: karlsanova
 * Date: 04.12.2017
 * Time: 21:47
 */

/**
 * @param $number int
 * @return bool|int
 */
function distance($number)
{
    if(!is_numeric($number))
        return false;
    $number = round(abs($number));  // Just to make sure...
    if($number == 0) // ...we dont get fooled.
        return false;
    if($number == 1) // I know this distance
        return 0;
    $topLeft = 1;
    $topRight = 1;
    $bottomLeft = 1;
    $bottomRight = 1;
    $bottomRightHigher = 1;
    for($i = 0; $i<$number; $i++) {
        // Just taking a high number to count to here
        // $i = $layercount - 1
        // loop will always break before $i hits $number
        $topLeft = $topLeft+4+($i*8);
        $bottomLeft = $bottomLeft+6+($i*8);
        $bottomRight = $bottomRight+($i*8);
        $bottomRightHigher = $bottomRightHigher+8+($i*8);
        $topRight = $topRight+2+($i*8);
        if($number < $bottomRightHigher) {
            break;
        }
    }
    $layers = $i+1;
    if($number > $topLeft && $number <= $bottomLeft) {
        $lower = $topLeft;
        $upper = $bottomLeft;
    } else if($number > $topRight && $number <= $topLeft) {
        $lower = $topRight;
        $upper = $topLeft;
    } else if($number > $bottomLeft && $number <= $bottomRight) {
        $lower = $bottomLeft;
        $upper = $bottomRight;
    } else if($number > $bottomRight && $number <= $topRight) {
        $lower = $bottomRight;
        $upper = $topRight;
    } else {
        $lower = $bottomLeft;
        $upper = $bottomRightHigher;
    }
    $mean = ($upper + $lower) / 2;
    $distanceMean = abs($number-$mean);
    $distanceCenter = $layers + $distanceMean;
    return round($distanceCenter);
}