aoc-2021/day04/day04.ts

import * as O from "fp-ts/Option";
import * as N from "fp-ts/number";

import { chunksOf, concat, every, exists, filter, findFirst, isOutOfBound, map, mapWithIndex, reduce, replicate, tail } from "fp-ts/lib/Array";
import { pipe } from "fp-ts/lib/function";
import { concatAll } from "fp-ts/lib/Monoid";
import { isEmpty } from "fp-ts/lib/string";

import { draws as testDraws, RawTable, tables as testTables } from "./input.test";
import { draws as inputDraws, tables as inputTables } from "./input";



type Value = {
  value: number,
  marked: boolean
};

type Table = {
  id: number;
  lastMarked?: number,
  won?: number;
  table: Value[][]
}


const parseTables = (tables: string) => pipe(
  tables.split("\n"),
  filter(s => !isEmpty(s)),
  chunksOf(5),
  map(table => pipe(table, map(row => row.split(" ").filter(n => !isEmpty(n)).map(s => parseInt(s)))))
);

const tables: Table[] = pipe(
  // testTables,
  parseTables(inputTables),
  mapWithIndex<RawTable, Table>((i, t) => ({
    id: i,
    table: pipe(t, map(r => pipe(r, map<number, Value>(v => ({ value: v, marked: false })))))
  }))
);

const draws: number[] =
  // testDraws;
inputDraws;



const product = (a: number) => (b: number) =>
  N.MonoidProduct.concat(a, b);

const result = (table: Table): number => pipe(
  [...table.table],
  reduce([] as Value[], (all, curr) => pipe(all, concat(curr))),
  filter(v => !v.marked),
  map(v => v.value),
  concatAll(N.MonoidSum),
  product(table.lastMarked ?? 1)
);

const evalRows = (table: Table): O.Option<number> => pipe(
  [...table.table],
  map(every(v => v.marked)),
  reduce(false, (acc, r) => acc || r),
  O.guard,
  O.map(() => result(table))
);

const evalColumns = (table: Table): O.Option<number> => pipe(
  [...table.table],
  reduce(
    replicate(table.table[0].length, true),
    (marks, row) => pipe(row, map(v => v.marked), mapWithIndex((i, m) => marks[i] && m))
  ),
  exists(m => m),
  O.guard,
  O.map(() => result(table))
);

const evalTable = (table: Table): Table => pipe(
  table,
  evalRows,
  O.alt(() => evalColumns(table)),
  O.fold(
    () => ({...table}),
    n => ({...table, won: n})
  )
);

const findValue = (draw: number) => (table: Table): O.Option<Value> => pipe(
  [...table.table],
  map(findFirst((v: Value) => v.value === draw)),
  reduce(O.none as O.Option<Value>, (v, o) => pipe(v, O.alt(() => o)))
);

const calc = (tables: Table[]) => (draw: number): Table[] => pipe(
  tables,
  filter(t => t.won === undefined),
  map(t => pipe(
    t,
    findValue(draw),
    O.fold<Value, Table>(
      () => ({
        ...t,
        lastMarked: undefined
      }),
      v => {
        v.marked = true;
        return {
          ...t,
          lastMarked: draw
        };
      }
    ),
    evalTable
  ))
);

const play = (ts: Table[], ds: number[]): Table[] => {
  if(isOutOfBound(0, ds)) {
    return ts;
  }
  const newTables = calc(ts)(ds[0]);
  console.log("new winners:", pipe(newTables, filter(t => t.won !== undefined)));
  return play(newTables, pipe(ds, tail, O.getOrElse(() => [] as number[])));
}


play(tables, draws);