From 9dcddd0081661eaf78a21490e66c5e90498bc1e8 Mon Sep 17 00:00:00 2001
From: Colin McMillen <colin@semicolin.games>
Date: Fri, 4 Dec 2020 23:15:13 -0500
Subject: [PATCH] okay, this is significantly nicer

---
 2020/Day04.cs | 45 ++++++++++++---------------------------------
 1 file changed, 12 insertions(+), 33 deletions(-)

diff --git a/2020/Day04.cs b/2020/Day04.cs
index 5f5a556..2cafc3c 100644
--- a/2020/Day04.cs
+++ b/2020/Day04.cs
@@ -55,10 +55,6 @@ namespace AdventOfCode {
       }
     }
 
-    static bool ValidateHairColor(string value) {
-      return Regex.IsMatch(value, @"^#[0-9a-f]{6}$");
-    }
-
     static bool IsValidPassport2(string input) {
       string[] fields = input.Split(' ');
       var fieldsPresent = new HashSet<string>();
@@ -69,35 +65,18 @@ namespace AdventOfCode {
         string[] tokens = field.Split(':');
         string key = tokens[0];
         string value = tokens[1];
-        fieldsPresent.Add(key);
-        if (key == "byr") {
-          if (!ValidateYear(value, 1920, 2002)) {
-            return false;
-          }
-        } else if (key == "iyr") {
-          if (!ValidateYear(value, 2010, 2020)) {
-            return false;
-          }
-        } else if (key == "eyr") {
-          if (!ValidateYear(value, 2020, 2030)) {
-            return false;
-          }
-        } else if (key == "hgt") {
-          if (!ValidateHeight(value)) {
-            return false;
-          }
-        } else if (key == "hcl") {
-          if (!ValidateHairColor(value)) {
-            return false;
-          }
-        } else if (key == "ecl") {
-          if (!validEyeColors.Contains(value)) {
-            return false;
-          }
-        } else if (key == "pid") {
-          if (!Regex.IsMatch(value, @"^[0-9]{9}$")) {
-            return false;
-          }
+        bool valid = key switch {
+          "byr" => ValidateYear(value, 1920, 2002),
+          "iyr" => ValidateYear(value, 2010, 2020),
+          "eyr" => ValidateYear(value, 2020, 2030),
+          "hgt" => ValidateHeight(value),
+          "hcl" => Regex.IsMatch(value, @"^#[0-9a-f]{6}$"),
+          "ecl" => validEyeColors.Contains(value),
+          "pid" => Regex.IsMatch(value, @"^[0-9]{9}$"),
+          _ => false
+        };
+        if (valid) {
+          fieldsPresent.Add(key);
         }
       }
       return fieldsPresent.IsSupersetOf(requiredFields);