day1 done

Author: spaenleh

Sources/AdventOfCode.swift

@@ -2,7 +2,7 @@ import ArgumentParser
 
 // Add each new day implementation to this array:
 let allChallenges: [any AdventDay] = [
-  Day00()
+  Day01()
 ]
 
 @main

Sources/Day01.swift

@@ -0,0 +1,34 @@
+import Algorithms
+
+struct Day01: AdventDay {
+  // Save your data in a corresponding text file in the `Data` directory.
+  var data: String
+
+  var lines: [[Substring.SubSequence]] {
+    data.split(separator: "\n").map { $0.split(separator: " ") }
+  }
+
+  // add here any computed values useful for the challenge
+
+  func part1() -> Int {
+    let listRight = lines.map { Int($0[0]) ?? 0 }.sorted()
+    let listLeft = lines.map { Int($0[1]) ?? 0 }.sorted()
+    var sum = 0
+    for (one, two) in zip(listLeft, listRight) {
+      sum += abs(one - two)
+    }
+    return sum
+  }
+
+  func part2() -> Int {
+    let left = lines.map { Int($0[0]) ?? 0 }.sorted()
+    let right = lines.map { Int($0[1]) ?? 0 }.sorted()
+
+    var similarity = 0
+    for elem in left {
+      let occurrences = right.filter { $0 == elem }.count
+      similarity += elem * occurrences
+    }
+    return similarity
+  }
+}

Tests/Day01.swift

@@ -0,0 +1,27 @@
+import Testing
+
+@testable import aoc
+
+@Suite("Day01")
+struct Day01Tests {
+  let testData = """
+    3   4
+    4   3
+    2   5
+    1   3
+    3   9
+    3   3
+    """
+
+  @Test("part1")
+  func testPart1() async throws {
+    let challenge = Day01(data: testData)
+    #expect(challenge.part1() == 11)
+  }
+
+  @Test("part2")
+  func testPart2() async throws {
+    let challenge = Day01(data: testData)
+    #expect(challenge.part2() == 31)
+  }
+}