Day 10: Hoof It
Megathread guidelines
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FAQ
- What is this?: Here is a post with a large amount of details: https://programming.dev/post/6637268
- Where do I participate?: https://adventofcode.com/
- Is there a leaderboard for the community?: We have a programming.dev leaderboard with the info on how to join in this post: https://programming.dev/post/6631465
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TypeScript
Maaaannnn. Today’s solution was really something. I actually got so confused initially that I unknowingly wrote the algorithm for part 2 before I even finished part 1! As an upside, however, I did expand my own Advent of Code standard library ;)
Solution
import { AdventOfCodeSolutionFunction } from "./solutions";
import { Grid } from "./utils/grids";
import { LinkedPoint } from "./utils/structures/linkedPoint";
import { makeGridFromMultilineString, SumArray } from "./utils/utils";
class TrailPoint extends LinkedPoint<number, TrailPoint> {
constructor(x: number, y: number, item: number, grid: Grid<TrailPoint>) {
super(x, y, item, grid);
}
lookAroundValid(): Array<TrailPoint> {
return this.lookAround().filter(v => v.item == this.item + 1);
}
findAllValidPeaks(): Array<TrailPoint> {
if (this.item == 9)
return [this];
// filter for distinct references (this theoretically saves time)
return [...(new Set(this.lookAroundValid().flatMap(v => v.findAllValidPeaks())))];
}
findAllValidPeaksWithReps(): Array<TrailPoint> {
if (this.item == 9)
return [this];
// don't filter
return this.lookAroundValid().flatMap(v => v.findAllValidPeaksWithReps());
}
}
export const solution_10: AdventOfCodeSolutionFunction = (input) => {
const map: Grid<TrailPoint> =
makeGridFromMultilineString(input)
.map((row) => row.map((item) => item != "." ? Number(item) : -1))
.map((row, y) => row.map((item, x) => new TrailPoint(x, y, item, undefined!)));
map.flat().forEach((v) => v.grid = map); // promise is a promise
const startNodes: Array<TrailPoint> = map.flat().filter(v => v.item == 0);
const part_1 = SumArray(startNodes.map(v => v.findAllValidPeaks().length));
const part_2 = SumArray(startNodes.map(v => v.findAllValidPeaksWithReps().length));
return {
part_1, // 557
part_2, // 1062
}
}
