split each day into a separate source file

2020/Day01.cs

@@ -0,0 +1,58 @@
+using System;
+using static System.Console;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Xunit;
+
+namespace AdventOfCode {
+
+  public class Day01 {
+
+    static int Part1(List<int> numbers) {
+      for (var i = 0; i < numbers.Count; i++) {
+        for (var j = i + 1; j < numbers.Count; j++) {
+          if (numbers[i] + numbers[j] == 2020) {
+            return numbers[i] * numbers[j];
+          }
+        }
+      }
+      throw new ArgumentException("no pair of numbers summed to 2020");
+    }
+
+    static int Part2(List<int> numbers) {
+      for (var i = 0; i < numbers.Count; i++) {
+        for (var j = i + 1; j < numbers.Count; j++) {
+          for (var k = j + 1; k < numbers.Count; k++) {
+            if (numbers[i] + numbers[j] + numbers[k] == 2020) {
+              return numbers[i] * numbers[j] * numbers[k];
+            }
+          }
+        }
+      }
+      throw new ArgumentException("no triple of numbers summed to 2020");
+    }
+
+    [Fact]
+    public static void Test() {
+      var emptyInput = new List<int>();
+      var bogusInput = new List<int>() {
+        111, 222, 333, 444, 555, 666, 777, 888, 999
+      };
+      var exampleInput = new List<int>() {
+        1721, 979, 366, 299, 675, 1456
+      };
+      var testInput = Util.ReadInts(Util.RootDir + "day01.txt");
+
+      Assert.Throws<ArgumentException>(() => Part1(emptyInput));
+      Assert.Throws<ArgumentException>(() => Part1(bogusInput));
+      Assert.Equal(514579, Part1(exampleInput));
+      Assert.Equal(355875, Part1(testInput));
+
+      Assert.Throws<ArgumentException>(() => Part2(emptyInput));
+      Assert.Throws<ArgumentException>(() => Part2(bogusInput));
+      Assert.Equal(241861950, Part2(exampleInput));
+      Assert.Equal(140379120, Part2(testInput));
+    }
+  }
+}

2020/Day02.cs

@@ -0,0 +1,62 @@
+using System;
+using static System.Console;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Xunit;
+
+namespace AdventOfCode {
+
+  public class Day02 {
+
+    static bool IsPasswordValid1(string spec) {
+      string[] tokens = spec.Split(' ');
+      string[] numbers = tokens[0].Split('-');
+      int min = int.Parse(numbers[0]);
+      int max = int.Parse(numbers[1]);
+      char required = tokens[1][0];
+      string password = tokens[2];
+
+      int count = 0;
+      for (int i = 0; i < password.Length; i++) {
+        if (password[i] == required) {
+          count++;
+        }
+      }
+      return min <= count && count <= max;
+    }
+
+    static bool IsPasswordValid2(string spec) {
+      string[] tokens = spec.Split(' ');
+      string[] numbers = tokens[0].Split('-');
+      int lowIndex = int.Parse(numbers[0]) - 1;
+      int highIndex = int.Parse(numbers[1]) - 1;
+      char required = tokens[1][0];
+      string password = tokens[2];
+      return
+        (password[lowIndex] == required && password[highIndex] != required) ||
+        (password[lowIndex] != required && password[highIndex] == required);
+    }
+
+    static int Part1() {
+      return File.ReadAllLines(Util.RootDir + "day02.txt").Count(IsPasswordValid1);
+    }
+
+    static int Part2() {
+      return File.ReadAllLines(Util.RootDir + "day02.txt").Count(IsPasswordValid2);
+    }
+
+    [Fact]
+    public static void Test() {
+      Assert.True(IsPasswordValid1("1-3 a: abcde"));
+      Assert.False(IsPasswordValid1("1-3 b: cdefg"));
+      Assert.True(IsPasswordValid1("2-9 c: ccccccccc"));
+      Assert.Equal(603, Part1());
+
+      Assert.True(IsPasswordValid2("1-3 a: abcde"));
+      Assert.False(IsPasswordValid2("1-3 b: cdefg"));
+      Assert.False(IsPasswordValid2("2-9 c: ccccccccc"));
+      Assert.Equal(404, Part2());
+    }
+  }
+}

2020/DayTemplate.cs

@@ -0,0 +1,24 @@
+using System;
+using static System.Console;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Xunit;
+
+namespace AdventOfCode {
+
+  public class DayXX {
+
+    static void Part1() {
+    }
+
+    static void Part2() {
+    }
+
+    [Fact(Skip = "template")]
+    public static void Test() {
+      Part1();
+      Part2();
+    }
+  }
+}

2020/Program.cs

@@ -7,114 +7,20 @@ using Xunit;
 
 namespace AdventOfCode {
 
-  public class Program {
+  public class Util {
-
+    public static string RootDir =
-    static string RootDir =
         Environment.GetEnvironmentVariable("HOME") + "/src/adventofcode/2020/";
 
-    static List<int> ReadInts(string filename) {
+    public static List<int> ReadInts(string filename) {
       string[] lines = File.ReadAllLines(filename);
       return lines.Select(int.Parse).ToList();
     }
+  }
 
-    static int Day1Part1(List<int> numbers) {
+  public class Program {
-      for (var i = 0; i < numbers.Count; i++) {
-        for (var j = i + 1; j < numbers.Count; j++) {
-          if (numbers[i] + numbers[j] == 2020) {
-            return numbers[i] * numbers[j];
-          }
-        }
-      }
-      throw new ArgumentException("no pair of numbers summed to 2020");
-    }
-
-    static int Day1Part2(List<int> numbers) {
-      for (var i = 0; i < numbers.Count; i++) {
-        for (var j = i + 1; j < numbers.Count; j++) {
-          for (var k = j + 1; k < numbers.Count; k++) {
-            if (numbers[i] + numbers[j] + numbers[k] == 2020) {
-              return numbers[i] * numbers[j] * numbers[k];
-            }
-          }
-        }
-      }
-      throw new ArgumentException("no triple of numbers summed to 2020");
-    }
-
-    [Fact]
-    static void Day1Test() {
-      var emptyInput = new List<int>();
-      var bogusInput = new List<int>() {
-        111, 222, 333, 444, 555, 666, 777, 888, 999
-      };
-      var exampleInput = new List<int>() {
-        1721, 979, 366, 299, 675, 1456
-      };
-      var testInput = ReadInts(RootDir + "day01.txt");
-
-      Assert.Throws<ArgumentException>(() => Day1Part1(emptyInput));
-      Assert.Throws<ArgumentException>(() => Day1Part1(bogusInput));
-      Assert.Equal(514579, Day1Part1(exampleInput));
-      Assert.Equal(355875, Day1Part1(testInput));
-
-      Assert.Throws<ArgumentException>(() => Day1Part2(emptyInput));
-      Assert.Throws<ArgumentException>(() => Day1Part2(bogusInput));
-      Assert.Equal(241861950, Day1Part2(exampleInput));
-      Assert.Equal(140379120, Day1Part2(testInput));
-    }
-
-    static bool IsPasswordValid1(string spec) {
-      string[] tokens = spec.Split(' ');
-      string[] numbers = tokens[0].Split('-');
-      int min = int.Parse(numbers[0]);
-      int max = int.Parse(numbers[1]);
-      char required = tokens[1][0];
-      string password = tokens[2];
-
-      int count = 0;
-      for (int i = 0; i < password.Length; i++) {
-        if (password[i] == required) {
-          count++;
-        }
-      }
-      return min <= count && count <= max;
-    }
-
-    static bool IsPasswordValid2(string spec) {
-      string[] tokens = spec.Split(' ');
-      string[] numbers = tokens[0].Split('-');
-      int lowIndex = int.Parse(numbers[0]) - 1;
-      int highIndex = int.Parse(numbers[1]) - 1;
-      char required = tokens[1][0];
-      string password = tokens[2];
-      return
-        (password[lowIndex] == required && password[highIndex] != required) ||
-        (password[lowIndex] != required && password[highIndex] == required);
-    }
-
-    static int Day2Part1() {
-      return File.ReadAllLines(RootDir + "day02.txt").Count(IsPasswordValid1);
-    }
-
-    static int Day2Part2() {
-      return File.ReadAllLines(RootDir + "day02.txt").Count(IsPasswordValid2);
-    }
-
-    [Fact]
-    static void Day2Test() {
-      Assert.True(IsPasswordValid1("1-3 a: abcde"));
-      Assert.False(IsPasswordValid1("1-3 b: cdefg"));
-      Assert.True(IsPasswordValid1("2-9 c: ccccccccc"));
-      Assert.Equal(603, Day2Part1());
-
-      Assert.True(IsPasswordValid2("1-3 a: abcde"));
-      Assert.False(IsPasswordValid2("1-3 b: cdefg"));
-      Assert.False(IsPasswordValid2("2-9 c: ccccccccc"));
-      Assert.Equal(404, Day2Part2());
-    }
-
     static void Main(string[] args) {
-      Day2Test();
+      Day01.Test();
+      Day02.Test();
     }
   }
 }