d3: add (a little bit more) concise solution

2022/d3/run.sh

@@ -3,8 +3,9 @@
 # Runs deno at src/d3_deno.ts with arguments ["example.txt"]
 echo "example.txt"
 deno run --allow-read "${PWD}/src/d3_deno.ts" "${PWD}/data/example.txt"
+deno run --allow-read "${PWD}/src/d3_deno_concise.ts" "${PWD}/data/example.txt"
 
 echo "submission.txt"
 deno run --allow-read "${PWD}/src/d3_deno.ts" "${PWD}/data/submission.txt"
-
+deno run --allow-read "${PWD}/src/d3_deno_concise.ts" "${PWD}/data/submission.txt"
 

2022/d3/src/d3_deno.ts

@@ -12,12 +12,6 @@ function priority(chr: string) {
 		: (ord(chr) - ord('A') + 27);
 }
 
-if (Deno.args.length < 1) {
-	throw Error(
-		'd3_deno.ts expects a single argument that points to AOC\'s day 3 input file',
-	);
-}
-
 async function main(fileLoc: string) {
 	// part 1
 	const text = await Deno.readTextFile(fileLoc);
@@ -71,6 +65,12 @@ async function main(fileLoc: string) {
 	console.log('part 2:', badges.reduce((a,b)=>a+b));
 }
 
+if (Deno.args.length < 1) {
+	throw Error(
+		'd3_deno.ts expects a single argument that points to AOC\'s day 3 input file',
+	);
+}
+
 const fileLoc = Deno.args[0];
 await main(fileLoc);
 

2022/d3/src/d3_deno_concise.ts

@@ -0,0 +1,60 @@
+// Usable by Windows and UNIX
+const LINE_SPLIT = (/\r?\n/);
+
+async function main(fileLoc: string) {
+	const input = await Deno.readTextFile(fileLoc);
+	const ord = (s: string) => s.charCodeAt(0);
+	const prioritized = input.split(LINE_SPLIT).map((line) => line.trim())
+		.filter((line) => line.length != 0)
+		.map((line) =>
+			[...line].map((e) => e.charCodeAt(0))
+				.map((e) =>
+					e - ((ord('a') <= e && e <= ord('z'))
+						? (ord('a') - 1)
+						: (ord('A') - 27))
+				)
+		);
+	const retain = <T>(a: T[], b: T[]) => {
+		const bSet = new Set(b);
+		return a.filter((e) => bSet.has(e));
+	};
+	const halves = <T>(a: T[]) =>
+		[a.slice(0, a.length / 2), a.slice(a.length / 2, a.length)] as const;
+	console.log(
+		'part 1',
+		prioritized
+			.map((sack) => retain(...halves(sack))[0]).reduce((a, b) => a + b),
+	);
+	const arrayGroupBy = <T, F>(a: T[], groupFn: (elem: T, idx: number) => F) =>
+		a.reduce((ret, e, idx) => {
+			const identity = groupFn(e, idx);
+			if (!ret.groupMap.has(identity)) {
+				ret.groupMap.set(identity, ret.groupKeys.length);
+				ret.groupKeys.push(identity);
+				ret.groups.push([identity, []]);
+			}
+			ret.groups[ret.groupMap.get(identity)!][1].push(e);
+			return ret;
+		}, {
+			groupKeys: new Array<F>(),
+			groupMap: new Map<F, number>(),
+			groups: new Array<[F, T[]]>(),
+		}).groups;
+
+	console.log(
+		'part 2',
+		arrayGroupBy(prioritized, (_, idx) => Math.floor(idx / 3))
+			.map(([_idx, sacks]) => sacks)
+			.map((groupOf3) => groupOf3.reduce((a, b) => retain(a, b))[0])
+			.reduce((a, b) => a + b),
+	);
+}
+
+if (Deno.args.length < 1) {
+	throw Error(
+		'd3_deno.ts expects a single argument that points to AOC\'s day 3 input file',
+	);
+}
+
+const fileLoc = Deno.args[0];
+await main(fileLoc);