Merge pull request #1 from kocmana/feature/dec-06

Day 6 WIP

src/main/java/at/kocmana/aoc23/common/Parser.java

@@ -0,0 +1,21 @@
+package at.kocmana.aoc23.common;
+
+import static java.util.function.Predicate.not;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class Parser {
+
+  private Parser() {
+
+  }
+
+  public static List<Integer> toNumberList(String input) {
+    return Arrays.stream(input.trim().split("\\s+"))
+        .filter(not(String::isBlank))
+        .map(Integer::parseInt)
+        .toList();
+  }
+
+}

src/main/java/at/kocmana/aoc23/dec06/WaitForIt.java

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+package at.kocmana.aoc23.dec06;
+
+import static at.kocmana.aoc23.common.Parser.toNumberList;
+
+import java.util.List;
+import java.util.stream.IntStream;
+
+public class WaitForIt {
+
+  public static void main(String[] args) {
+
+  }
+
+  static List<Race> parseRaces(String input) {
+    input = input.replace("Time:", "")
+        .replace("Distance:", "")
+        .trim();
+    var lines = input.split("\\n");
+    var times = toNumberList(lines[0]);
+    var distances = toNumberList(lines[1]);
+
+    assert (times.size() == distances.size());
+
+    return IntStream.range(0, times.size())
+        .mapToObj(i -> new Race(times.get(i), distances.get(i)))
+        .toList();
+  }
+
+  static long assessNumberOfPossibleWins(Race race) {
+    return IntStream.range(1, race.time())
+        .mapToObj(i -> {
+          var distance = calculateDistance(i, race.time());
+          return new RaceOutcome(
+              distance,
+              isWin(race.distanceToBeat(), distance)
+          );
+        })
+        .filter(RaceOutcome::isWin)
+        .count();
+  }
+
+  static int calculateDistance(int durationButtonPressed, int totalRaceDuration) {
+    var remainingTime = totalRaceDuration - durationButtonPressed;
+    var speed = durationButtonPressed;
+    return speed * remainingTime;
+  }
+
+  static boolean isWin(int distanceToBeat, int distance) {
+    return distanceToBeat < distance;
+  }
+
+  long generateNumberOfWays(String input) {
+    return parseRaces(input).stream()
+        .map(WaitForIt::assessNumberOfPossibleWins)
+        .reduce(1L, (i, j) -> i * j);
+  }
+}
+
+record Race(
+    int time,
+    int distanceToBeat
+) {
+}
+
+record RaceOutcome(
+    int distance,
+    boolean isWin
+) {
+}

src/test/java/at/kocmana/aoc23/dec06/WaitForItTest.java

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+package at.kocmana.aoc23.dec06;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+class WaitForItTest {
+
+  @Test
+  void canParse() {
+    //given
+    var input = """
+        Time:      7  15   30
+        Distance:  9  40  200
+        """;
+
+    //when
+    var actualResult = WaitForIt.parseRaces(input);
+
+    //then
+    assertThat(actualResult).isNotNull()
+        .hasSize(3)
+        .contains(
+            new Race(7, 9),
+            new Race(15, 40),
+            new Race(30, 200)
+        );
+  }
+
+}