add utils and beatify solution for day1

Author: spaenleh

Sources/Array+Utils.swift

@@ -0,0 +1,7 @@
+import Foundation
+
+extension Array where Element == Int {
+  var sum: Int {
+    self.reduce(0, +)
+  }
+}

Sources/Day01.swift

@@ -1,37 +1,27 @@
 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: " ") }
+  var lines: [[Int]] {
+    data.lines().map { $0.integers() }
   }
 
   var left: [Int] {
-    lines.map { Int($0[0]) ?? 0 }.sorted()
+    lines.map { $0[0] }.sorted()
   }
 
   var right: [Int] {
-    lines.map { Int($0[1]) ?? 0 }.sorted()
+    lines.map { $0[1] }.sorted()
   }
 
-  // add here any computed values useful for the challenge
-
   func part1() -> Int {
-    var sum = 0
-    for (one, two) in zip(left, right) {
-      sum += abs(one - two)
-    }
-    return sum
+    zip(left, right).map { l, r in abs(l - r) }.sum
   }
 
   func part2() -> Int {
-    var similarity = 0
-    for elem in left {
-      let occurrences = right.filter { $0 == elem }.count
-      similarity += elem * occurrences
-    }
-    return similarity
+    left.map { elem in
+      elem * right.filter { $0 == elem }.count
+    }.sum
   }
 }

Sources/String+Parsing.swift

@@ -0,0 +1,20 @@
+import Algorithms
+import Foundation
+
+extension StringProtocol {
+  func trimmed() -> String {
+    self.trimmingCharacters(in: .whitespacesAndNewlines)
+  }
+
+  func lines() -> [SubSequence] {
+    self.split(separator: "\n")
+  }
+
+  func integers(separator: String = " ") -> [Int] {
+    self.split(separator: separator).map { Int($0) }.compactMap { $0 }
+  }
+
+  func doubles(separator: String = " ") -> [Double] {
+    self.split(separator: separator).map { Double($0) }.compactMap { $0 }
+  }
+}

Tests/Array+Utils.swift

@@ -0,0 +1,14 @@
+import Testing
+
+@testable import aoc
+
+@Suite("Array extensions")
+struct ArrayExtensions {
+  @Test("Sum")
+  func testSum() async throws {
+    #expect([1, 2, 3, 4, 5, 6].sum == 21)
+    #expect([].sum == 0)
+    #expect([].sum == 0)
+  }
+
+}

Tests/String+Parsing.swift

@@ -0,0 +1,29 @@
+import Testing
+
+@testable import aoc
+
+@Suite("String extensions")
+struct StringExtensions {
+  @Test("Trimming")
+  func testTrimming() async throws {
+    #expect("   hello    ".trimmed() == "hello")
+    #expect("\n\nhello\n".trimmed() == "hello")
+  }
+
+  @Test("Lines Parsing")
+  func testLinesParsing() async throws {
+    #expect("".lines() == [])
+    #expect("\n\n".lines() == [])
+    #expect("1\n2\n3\n".lines() == ["1", "2", "3"])
+    #expect("1\n\n2".lines() == ["1", "2"])
+  }
+
+  @Test("Value parsing")
+  func testValueParsing() async throws {
+    #expect("".integers() == [])
+    #expect("a".integers() == [])
+    #expect("a 1 toto 1.3".integers() == [1])
+    #expect("a 1 toto 1.3".doubles() == [1.0, 1.3])
+    #expect("1 2 3 4".integers() == [1, 2, 3, 4])
+  }
+}