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part 2, attempt 1 -- brute force, no bueno
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+66
-2
2023/day05/part2.ts
+66
-2
2023/day05/part2.ts
···
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import { assert } from "https://deno.land/std@0.208.0/assert/mod.ts";
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if (import.meta.main) {
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const input = (
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await Deno.readFile("input").then((bytes) =>
···
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console.log(answer(input));
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}
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type Range = {
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fromStart: number;
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toStart: number;
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range: number;
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};
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type MapRanges = {
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from: string;
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to: string;
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ranges: Range[];
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};
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export function answer(input: string): number {
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console.log(input);
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return 42;
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const [seedLine, _, ...mapLines] = input.split("\n");
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const seedRanges = seedLine
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.replace("seeds: ", "")
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.split(" ")
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.map((x) => parseInt(x));
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const seeds = [];
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for (let i = 0; i < seedRanges.length; i += 2) {
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const from = seedRanges[i];
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const to = from + seedRanges[i + 1];
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for (let j = 0; j < to - from; j++) {
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seeds.push(seedRanges[i] + j);
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}
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}
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const mapRanges: MapRanges[] = mapLines
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.join("\n")
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.split("\n\n")
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.map((mapLine) => {
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const [fromToLine, ...rangeLines] = mapLine.split("\n");
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const [_, from, to] = fromToLine.match(/([a-z]+)-to-([a-z]+) map/)!;
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const ranges = rangeLines.map((rangeLine) => {
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const [toStart, fromStart, range] = rangeLine
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.split(" ")
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.map((n) => parseInt(n));
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return { fromStart, toStart, range };
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});
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return { from, to, ranges };
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});
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// start at `from: seed` to `to: location`
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const locationNumbers = seeds.map((s) => getLocationNumber(s, mapRanges));
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return Math.min(...locationNumbers);
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}
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function getLocationNumber(seed: number, mapRanges: MapRanges[]): number {
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let current = "seed";
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let currentNum = seed;
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while (current !== "location") {
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const mapRange = mapRanges.find(({ from }) => from === current);
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assert(mapRange, `mapRange not found for: ${current}`);
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const range = mapRange.ranges.find(
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(r) => currentNum >= r.fromStart && currentNum <= r.fromStart + r.range,
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);
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if (range) currentNum = currentNum + (range.toStart - range.fromStart);
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current = mapRange.to;
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}
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return currentNum;
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}
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2023/day05/test.ts
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2023/day05/test.ts
···
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"50 98 2",
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"52 50 48",
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"",
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// 13 + (15-0)
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"soil-to-fertilizer map:",
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"0 15 37",
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"37 52 2",
···
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assertEquals(p1.answer(examples), 35);
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});
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// Deno.test("part2", () => {
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// const examples = ["abc", "def"].join("\n");
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// assertEquals(p2.answer(examples), 42);
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// });
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Deno.test("part2", () => {
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const examples = [
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"seeds: 79 14 55 13",
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"",
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"seed-to-soil map:",
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"50 98 2",
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"52 50 48",
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"",
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// 13 + (15-0)
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"soil-to-fertilizer map:",
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"0 15 37",
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"37 52 2",
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"39 0 15",
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"",
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"fertilizer-to-water map:",
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"49 53 8",
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"0 11 42",
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"42 0 7",
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"57 7 4",
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"",
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"water-to-light map:",
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"88 18 7",
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"18 25 70",
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"",
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"light-to-temperature map:",
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"45 77 23",
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"81 45 19",
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"68 64 13",
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"",
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"temperature-to-humidity map:",
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"0 69 1",
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"1 0 69",
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"",
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"humidity-to-location map:",
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"60 56 37",
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"56 93 4",
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].join("\n");
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assertEquals(p2.answer(examples), 46);
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});