43 lines
1.2 KiB
JavaScript
43 lines
1.2 KiB
JavaScript
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const fs = require('fs');
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const input = fs.readFileSync('./input.txt', 'utf-8');
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const inputTiles = input.split('\n\n');
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// it is implied that the image is a square, which makes it far simpler.
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const sideLength = Math.sqrt(inputTiles.length);
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const tileSize = 9
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let allBorders = new Map();
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console.log(sideLength);
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let tiles = [];
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inputTiles.forEach(inputTile => {
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tileLines = inputTile.split('\n');
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let tileID = tileLines[0].slice(5, 9);
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let tileData = tileLines.slice(1)
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let borders = [
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tileData[0],
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tileData[tileSize],
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tileData.reduce((a,b)=>a+b[0], ''),
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tileData.reduce((a,b)=>a+b[tileSize], '')
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];
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borders.forEach(border=>{
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if (!allBorders.has(border)) {
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allBorders.set(border, 1)
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} else {
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allBorders.set(border, allBorders.get(border) + 1)
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}
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})
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tiles.push({tileID, borders})
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})
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function reverseString(str) {
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return (str === '') ? '' : reverseString(str.substr(1)) + str.charAt(0);
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}
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let runningTotal = 1;
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tiles.forEach(tile => {
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if (tile.borders.reduce((a, border) => a + allBorders.get(border) + (allBorders.get(reverseString(border))||0), -4) == 2) {
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console.log(tile.tileID)
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runningTotal *= tile.tileID
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}
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})
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console.log(runningTotal)
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