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import { Observable, of } from "rxjs";
import { concatAll, count, filter, groupBy, map, mergeMap, reduce, take, tap } from 'rxjs/operators';
import { ExerciseModuleFunc } from "../types";
type Coords = [number, number];
const SLOPES: Coords[] = [
[1, 1],
[3, 1],
[5, 1],
[7, 1],
[1, 2]
];
interface Observation {
slope: Coords;
coords: Coords;
}
const day3: ExerciseModuleFunc = async (input: string) => {
const lines = input.split("\n");
const my = lines.length;
const mx = lines[0].length;
const isTree = (x: number, y: number): boolean => lines[y][x % mx] === "#";
const indexObs = new Observable<Observation>(sub => {
for (const slope of SLOPES) {
for (let y = 0, x = 0; y < my; y += slope[1], x += slope[0]) {
if (isTree(x, y)) {
sub.next({ slope, coords: [x, y] });
}
}
}
sub.complete();
})
const prom1 = indexObs.pipe(
groupBy(obs => obs.slope),
mergeMap((grp$) => grp$.pipe(count())),
tap(console.log),
reduce((acc, val) => acc * val)
).toPromise();
return Promise.all([prom1]);
}
export default day3;
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