From 5045284462c8e67a5430367c5c92398f0ed7e5fb Mon Sep 17 00:00:00 2001
From: Jan Tuomi <jans.tuomi@gmail.com>
Date: Wed, 2 Dec 2020 09:57:07 +0200
Subject: Solve 2.2

---
 day2/index.ts | 44 ++++++++++++++++++++++++++++++++++++++------
 1 file changed, 38 insertions(+), 6 deletions(-)

diff --git a/day2/index.ts b/day2/index.ts
index e42e005..8b3199a 100644
--- a/day2/index.ts
+++ b/day2/index.ts
@@ -2,14 +2,21 @@ import { of } from "rxjs";
 import { concatAll, count, filter, map, take } from 'rxjs/operators';
 import { ExerciseModuleFunc } from "../types";
 
-interface Row {
+interface Row1 {
   min: number;
   max: number;
   letter: string;
   pwd: string;
 }
 
-const parse = (line: string): Row => {
+interface Row2 {
+  index1: number;
+  index2: number;
+  letter: string;
+  pwd: string;
+}
+
+const parse1 = (line: string): Row1 => {
   const re = /(\d+)-(\d+) (\w{1}): (\w+)/;
   const match = line.match(re);
 
@@ -21,7 +28,19 @@ const parse = (line: string): Row => {
   }
 }
 
-const isValid = (r: Row): boolean => {
+const parse2 = (line: string): Row2 => {
+  const re = /(\d+)-(\d+) (\w{1}): (\w+)/;
+  const match = line.match(re);
+
+  return {
+    index1: Number(match[1]) - 1,
+    index2: Number(match[2]) - 1,
+    letter: match[3],
+    pwd: match[4]
+  }
+}
+
+const isValid1 = (r: Row1): boolean => {
   let count = 0;
   r.pwd.split("").forEach(char => {
     if (char === r.letter) {
@@ -31,17 +50,30 @@ const isValid = (r: Row): boolean => {
   return count >= r.min && count <= r.max;
 }
 
+const isValid2 = (r: Row2): boolean => {
+  const a = r.pwd[r.index1] === r.letter;
+  const b = r.pwd[r.index2] === r.letter;
+  return (a && !b) || (!a && b);
+}
+
 const day2: ExerciseModuleFunc = async (input: string) => {
   const lines = input.split("\n");
 
   const prom1 = of(lines).pipe(
     concatAll(),
-    map(parse),
-    filter(isValid),
+    map(parse1),
+    filter(isValid1),
+    count()
+  ).toPromise();
+
+  const prom2 = of(lines).pipe(
+    concatAll(),
+    map(parse2),
+    filter(isValid2),
     count()
   ).toPromise();
 
-  return [await prom1];
+  return [await prom1, await prom2];
 }
 
 export default day2;
-- 
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