Add 2024, day 1, part 2

danielctull · Dec 1, 2024 · 662e816 · 662e816
1 parent 1b85ef3
commit 662e816
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Showing 2 changed files with 18 additions and 3 deletions.
diff --git a/Year2024/Sources/Day01.swift b/Year2024/Sources/Day01.swift
@@ -20,7 +20,15 @@ public enum Day01: Day {
     }
 
     public static func part2(_ input: Input) throws -> Int {
-        0
+        let rows = try input.lines
+            .map {
+                let values = $0.split(whereSeparator:(\.isWhitespace))
+                return try (Int(values.first.unwrapped), Int(values.last.unwrapped))
+            }
+        let columns = rotate(rows)
+        let lhs = columns.0
+        let rhs = columns.1
+        return lhs.map { $0 * rhs.count(of: $0) }.sum
     }
 }
 

diff --git a/Year2024/Tests/Day01Tests.swift b/Year2024/Tests/Day01Tests.swift
@@ -22,11 +22,18 @@ final class Day01Tests: XCTestCase {
     }
 
     func testPart2Examples() throws {
-        XCTAssertEqual(try Day01.part2([]), 0)
+        XCTAssertEqual(try Day01.part2([
+            "3   4",
+            "4   3",
+            "2   5",
+            "1   3",
+            "3   9",
+            "3   3",
+        ]), 31)
     }
 
     func testPart2Puzzle() throws {
         let input = try Bundle.module.input(named: "Day01")
-        XCTAssertEqual(try Day01.part2(input), 0)
+        XCTAssertEqual(try Day01.part2(input), 23741109)
     }
 }