part 2

2022/02/part1.js

@@ -1,29 +1,32 @@
 import * as R from "remeda";
 import { test, expect } from "vitest";
 import fs from "fs-extra";
-import path from 'path';
+import path from "path";
 
-import { spy } from '../01/main.js';
+import { spy } from "../01/main.js";
 
 export const sampleInput = `A Y
 B X
 C Z`;
 
-export const puzzleInput =
-  fs.readFileSync( path.join( path.dirname(import.meta.url), "input").replace('file:',''), "utf8");
+export const puzzleInput = fs.readFileSync(
+  path.join(path.dirname(import.meta.url), "input").replace("file:", ""),
+  "utf8"
+);
 
 const playMap = {
-    X: 'A', // rock
-    Y: 'B', // paper
-    Z: 'C', // scissors
-}
+  X: "A", // rock
+  Y: "B", // paper
+  Z: "C", // scissors
+};
 
 export const parseInput = R.createPipe(
-    text => text.split("\n"),
-    R.map( entry => entry.split(' ') ),
-    R.map( ([a,b]) => [a,playMap[b]] ),
-)
+  (text) => text.split("\n"),
+  R.filter(R.identity), // remove last line
+  R.map((entry) => entry.split(" "))
+);
 
+export const movePositions = ["A", "B", "C"];
 
 const playScore = {
   A: 1,
@@ -35,24 +38,26 @@ const draw = 3;
 const lost = 0;
 const win = 6;
 
-const outcome = ( opponent, me ) => {
-    if( opponent === me ) return draw;
-    if( opponent === 'A' ) {
-        return me === 'C' ? lost : win;
+const outcome = (opponent, me) => {
+  if (opponent === me) return draw;
+  if (opponent === "A") {
+    return me === "C" ? lost : win;
   }
-    if( opponent === 'B' ) {
-        return me === 'A' ? lost : win;
+  if (opponent === "B") {
+    return me === "A" ? lost : win;
   }
-    return me === 'B' ? lost : win;
-}
+  return me === "B" ? lost : win;
+};
 
-export const mapScores = ([opponent,me]) => [ outcome(opponent,me), playScore[me] ];
+export const mapScores = ([opponent, me]) => [
+  outcome(opponent, me),
+  playScore[me],
+];
 
 export const solutionPart1 = R.createPipe(
   parseInput,
-    R.filter( ([a]) => a  ), // remove last line
-    R.map( mapScores ),
-    R.map( R.sumBy(R.identity) ),
+  R.map(([a, b]) => [a, playMap[b]]),
+  R.map(mapScores),
+  R.map(R.sumBy(R.identity)),
   R.sumBy(R.identity)
 );
-

2022/02/part2.js

@@ -0,0 +1,25 @@
+import * as R from "remeda";
+
+import { movePositions, mapScores, playMap, parseInput } from "./part1.js";
+
+function calculateMove(opponent, verdict) {
+  const incr = {
+    Y: 0,
+    X: 2,
+    Z: 1,
+  };
+
+  const index =
+    (movePositions.findIndex((x) => x === opponent) + incr[verdict]) %
+    movePositions.length;
+
+  return movePositions[index];
+}
+
+export const solutionPart2 = R.createPipe(
+  parseInput,
+  R.map(([a, b]) => [a, calculateMove(a, b)]),
+  R.map(mapScores),
+  R.map(R.sumBy(R.identity)),
+  R.sumBy(R.identity)
+);

2022/02/test.js

@@ -1,28 +1,41 @@
-import { test, expect } from "vitest";
+import { test, expect, describe } from "vitest";
 
-import { expectSolution } from '../01/main.js';
-import { parseInput, sampleInput, puzzleInput, mapScores, solutionPart1 } from './part1.js';
+import { expectSolution } from "../01/main.js";
+import {
+  parseInput,
+  sampleInput,
+  puzzleInput,
+  mapScores,
+  solutionPart1,
+} from "./part1.js";
+import { solutionPart2 } from "./part2.js";
 
-test( "input parsing", () => {
-    expect(parseInput(sampleInput)).toEqual([['A','B'],['B','A'],['C','C']]);
-});
+describe("part 1", () => {
+  test("input parsing", () => {
+    expect(parseInput(sampleInput)).toEqual([
+      ["A", "Y"],
+      ["B", "X"],
+      ["C", "Z"],
+    ]);
+  });
 
-test( "mapScore", () => {
-    expect( mapScores(['A','B']) ).toEqual([6,2]);
-    expect( mapScores(['B','A']) ).toEqual([0,1]);
-    expect( mapScores(['C','C']) ).toEqual([3,3]);
-});
+  test("mapScore", () => {
+    expect(mapScores(["A", "B"])).toEqual([6, 2]);
+    expect(mapScores(["B", "A"])).toEqual([0, 1]);
+    expect(mapScores(["C", "C"])).toEqual([3, 3]);
+  });
 
-test( "part 1, sample", () => {
-    expect(
-        solutionPart1(sampleInput)
-    ).toEqual(15)
+  test("part 1, sample", () => {
+    expect(solutionPart1(sampleInput)).toEqual(15);
+  });
 
-});
-
-test("part 1", () => {
+  test("solution", () => {
     expectSolution(solutionPart1(puzzleInput)).toEqual(12458);
+  });
 });
 
-test.todo("part 2", () => {
+describe("part 2", () => {
+  test("part 2", () => {
+    expectSolution(solutionPart2(puzzleInput)).toEqual(12683);
+  });
 });