Cleaning solution for 2023, Day 6

zodac · Dec 9, 2023 · 79d450d · 79d450d
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commit 79d450d
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Showing 2 changed files with 40 additions and 37 deletions.
diff --git a/2023/src/main/java/me/zodac/advent/Day06.java b/2023/src/main/java/me/zodac/advent/Day06.java
@@ -33,35 +33,49 @@ private Day06() {
 
     }
 
-    private record Race(long time, long distance) {
-
-    }
-
     /**
-     * Part 1.
+     * We are given a {@link List} of {@link String}s, representing a number of {@link Race}s. For each {@link Race} we can 'charge' up our velocity,
+     * and use the remaining time to complete the required distance. We count the number of ways to win the {@link Race}s, then multiply them up.
+     *
+     * <p>
+     * if {@code isMultipleRaces} is {@code true}, each column of the input is referring to a separate {@link Race}, otherwise all columns should be
+     * concatenated to create one large {@link Race}.
      *
-     * @param values the input values
-     * @return the part 1 result
+     * @param values          the input {@link Race}s
+     * @param isMultipleRaces whether the input is multiple {@link Race}s or a single large {@link Race}
+     * @return the number of ways to win the supplied{@link Race}s
      */
-    public static long part1(final List<String> values) {
-        final Collection<Race> races = new ArrayList<>();
+    public static long countNumberOfWaysToWin(final List<String> values, final boolean isMultipleRaces) {
+        return parseRaces(values, isMultipleRaces)
+            .stream()
+            .mapToLong(Day06::countWaysToWinRace)
+            .reduce(1L, (first, second) -> first * second);
+    }
 
+    private static Collection<Race> parseRaces(final List<String> values, final boolean isMultipleRaces) {
         final List<Long> times = StringUtils.collectNumbersInOrder(values.getFirst());
         final List<Long> distances = StringUtils.collectNumbersInOrder(values.getLast());
+        final Collection<Race> races = new ArrayList<>();
 
-        for (int i = 0; i < times.size(); i++) {
-            races.add(new Race(times.get(i), distances.get(i)));
-        }
+        if (isMultipleRaces) {
+            for (int i = 0; i < times.size(); i++) {
+                races.add(new Race(times.get(i), distances.get(i)));
+            }
+        } else {
+            final StringBuilder timeBuilder = new StringBuilder();
+            final StringBuilder distanceBuilder = new StringBuilder();
+            for (int i = 0; i < times.size(); i++) {
+                timeBuilder.append(times.get(i));
+                distanceBuilder.append(distances.get(i));
+            }
 
-        long total = 1;
-        for (final Race race : races) {
-            final long val = countWinningOptions(race);
-            total *= val;
+            races.add(new Race(Long.parseLong(timeBuilder.toString()), Long.parseLong(distanceBuilder.toString())));
         }
-        return total;
+
+        return races;
     }
 
-    private static long countWinningOptions(final Race race) {
+    private static long countWaysToWinRace(final Race race) {
         int count = 0;
         for (int timeToHold = 1; timeToHold < race.time - 1; timeToHold++) {
             final long remainingTime = race.time - timeToHold;
@@ -75,23 +89,12 @@ private static long countWinningOptions(final Race race) {
     }
 
     /**
-     * Part 2.
+     * Simple record defining a race.
      *
-     * @param values the input values
-     * @return the part 2 result
+     * @param time     the time available
+     * @param distance the distance to travel
      */
-    public static long part2(final List<String> values) {
-        final List<Long> times = StringUtils.collectNumbersInOrder(values.getFirst());
-        final List<Long> distances = StringUtils.collectNumbersInOrder(values.getLast());
-
-        final StringBuilder timeBuilder = new StringBuilder();
-        final StringBuilder distanceBuilder = new StringBuilder();
-        for (int i = 0; i < times.size(); i++) {
-            timeBuilder.append(times.get(i));
-            distanceBuilder.append(distances.get(i));
-        }
+    private record Race(long time, long distance) {
 
-        final Race race = new Race(Long.parseLong(timeBuilder.toString()), Long.parseLong(distanceBuilder.toString()));
-        return countWinningOptions(race);
     }
 }
diff --git a/2023/src/test/java/me/zodac/advent/Day06Test.java b/2023/src/test/java/me/zodac/advent/Day06Test.java
@@ -35,11 +35,11 @@ public class Day06Test {
     void example() {
         final List<String> values = ExampleInput.readLines(INPUT_FILENAME);
 
-        final long part1Result = Day06.part1(values);
+        final long part1Result = Day06.countNumberOfWaysToWin(values, true);
         assertThat(part1Result)
             .isEqualTo(288L);
 
-        final long part2Result = Day06.part2(values);
+        final long part2Result = Day06.countNumberOfWaysToWin(values, false);
         assertThat(part2Result)
             .isEqualTo(71_503L);
     }
@@ -48,7 +48,7 @@ void example() {
     void part1() {
         final List<String> values = PuzzleInput.readLines(INPUT_FILENAME);
 
-        final long part1Result = Day06.part1(values);
+        final long part1Result = Day06.countNumberOfWaysToWin(values, true);
         assertThat(part1Result)
             .isEqualTo(771_628L);
     }
@@ -57,7 +57,7 @@ void part1() {
     void part2() {
         final List<String> values = PuzzleInput.readLines(INPUT_FILENAME);
 
-        final long part2Result = Day06.part2(values);
+        final long part2Result = Day06.countNumberOfWaysToWin(values, false);
         assertThat(part2Result)
             .isEqualTo(27_363_861L);
     }