71 lines
1.6 KiB
JavaScript
71 lines
1.6 KiB
JavaScript
import fs from "fs-extra";
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import fp from "lodash/fp.js";
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import _ from "lodash";
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export const processInput = (input) =>
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fs.readFile(input, "utf8").then((content) => {
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let [coords, instructions] = content.split("\n\n");
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let grid = [];
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for (const [y, x] of coords
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.split("\n")
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.map((line) => line.split(",").map((x) => parseInt(x)))) {
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if (!grid[x]) grid[x] = [];
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grid[x][y] = true;
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}
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grid = [...grid];
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grid = grid.map((x) => (x ? [...x] : []));
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instructions = instructions
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.split("\n")
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.filter((x) => x)
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.map((line) => line.match(/([xy])=(\d+)/))
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.map(([_, direction, level]) => [direction, parseInt(level)]);
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return {
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grid,
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instructions,
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};
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});
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export function foldGrid(grid, direction, level) {
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if (direction === "x") {
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for (const row of grid) {
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if (!row) continue;
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const folded = row.splice(level);
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folded.forEach((v, i) => {
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if (i === 0) return;
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if (!v) return;
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row[level - i] = v;
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});
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}
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return grid;
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}
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const folded = grid.splice(level);
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folded.forEach((v, i) => {
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if (i === 0) return;
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if (!v) return;
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grid[level - i] = _.range(
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_.max([grid[level - i].length, folded[i].length])
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).map((j) => grid[level - i][j] || folded[i][j]);
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});
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return grid;
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}
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export function printGrid(grid) {
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return grid
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.map((line) => (line || []).map((x) => (x ? "#" : ".")).join(""))
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.join("\n");
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}
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export function solution({ grid, instructions }) {
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foldGrid(grid, ...instructions.shift());
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return _.sum(grid.flat());
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}
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