From 5c401d8ae0eeb3bcbc13f8f2793ee07a05d273f9 Mon Sep 17 00:00:00 2001
From: Hubert Van De Walle <hubv@protonmail.com>
Date: Wed, 2 Dec 2020 07:44:20 +0100
Subject: [PATCH] Use xor

---
 days/src/main/kotlin/Day02.kt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/days/src/main/kotlin/Day02.kt b/days/src/main/kotlin/Day02.kt
index 01be461..72d9020 100644
--- a/days/src/main/kotlin/Day02.kt
+++ b/days/src/main/kotlin/Day02.kt
@@ -19,7 +19,7 @@ class Day02(@Lines input: Input<List<String>>) {
     fun part1() = passwords.count { it.password.count { char -> char == it.letter } in it.range }
 
     fun part2() = passwords.count { (range, letter, pwd) ->
-        arrayOf(pwd[range.first -1], pwd[range.last - 1]).filter { it == letter }.size == 1
+        (pwd[range.first - 1] == letter) xor (pwd[range.last - 1] == letter)
     }
 }