Merge pull request #2 from kocmana/feature/dec-06

Day 6 - Part 1 and 2

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

@@ -2,13 +2,22 @@
 
 import static at.kocmana.aoc23.common.Parser.toNumberList;
 
+import at.kocmana.aoc23.common.ResourceToString;
 import java.util.List;
 import java.util.stream.IntStream;
 
-public class WaitForIt {
+public class WaitForItPartOne {
 
   public static void main(String[] args) {
+    var puzzleInput = ResourceToString.from("dec06", "WaitForItPartOne.txt");
+    var result = generateNumberOfWays(puzzleInput);
+    System.out.printf("Result: %d", result);
+  }
 
+  static long generateNumberOfWays(String input) {
+    return parseRaces(input).stream()
+        .map(WaitForItPartOne::assessNumberOfPossibleWins)
+        .reduce(1L, (i, j) -> i * j);
   }
 
   static List<Race> parseRaces(String input) {
@@ -22,7 +31,7 @@ static List<Race> parseRaces(String input) {
     assert (times.size() == distances.size());
 
     return IntStream.range(0, times.size())
-        .mapToObj(i -> new Race(times.get(i), distances.get(i)))
+        .mapToObj(i -> new Race(times.get((int) i), distances.get((int) i)))
         .toList();
   }
 
@@ -48,12 +57,6 @@ static int calculateDistance(int durationButtonPressed, int totalRaceDuration) {
   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(

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

@@ -0,0 +1,69 @@
+package at.kocmana.aoc23.dec06;
+
+import static java.util.function.Predicate.not;
+
+import at.kocmana.aoc23.common.ResourceToString;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.IntStream;
+import java.util.stream.LongStream;
+
+public class WaitForItPartTwo {
+
+  public static void main(String[] args) {
+    var puzzleInput = ResourceToString.from("dec06", "WaitForItPartTwo.txt");
+    var result = generateNumberOfWays(puzzleInput);
+    System.out.printf("Result: %d", result);
+  }
+
+  static long generateNumberOfWays(String input) {
+    var race = parseRaces(input).get(0);
+    return WaitForItPartTwo.assessNumberOfPossibleWins(race);
+  }
+
+  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();
+  }
+
+  public static List<Long> toNumberList(String input) {
+    return Arrays.stream(input.trim().split("\\s+"))
+        .filter(not(String::isBlank))
+        .map(Long::parseLong)
+        .toList();
+  }
+
+  static long assessNumberOfPossibleWins(Race race) {
+    return LongStream.range(1, race.time())
+        .map(pressedMs -> calculateDistance(pressedMs, race.time()))
+        .filter(distance ->  isWin(race.distanceToBeat(), distance))
+        .count();
+  }
+
+  static long calculateDistance(long durationButtonPressed, long totalRaceDuration) {
+    var remainingTime = totalRaceDuration - durationButtonPressed;
+    var speed = durationButtonPressed;
+    return speed * remainingTime;
+  }
+
+  static Boolean isWin(long distanceToBeat, long distance) {
+    return distanceToBeat < distance;
+  }
+
+  record Race(
+      long time,
+      long distanceToBeat
+  ) {
+  }
+
+}

src/main/resources/dec06/WaitForItPartOne.txt

@@ -0,0 +1,2 @@
+Time:        59     79     65     75
+Distance:   597   1234   1032   1328

src/main/resources/dec06/WaitForItPartTwo.txt

@@ -0,0 +1,2 @@
+Time:        59796575
+Distance:   597123410321328

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

@@ -0,0 +1,69 @@
+package at.kocmana.aoc23.dec06;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class WaitForItPartOneTest {
+
+  @Test
+  void canParse() {
+    //given
+    var input = """
+        Time:      7  15   30
+        Distance:  9  40  200
+        """;
+
+    //when
+    var actualResult = WaitForItPartOne.parseRaces(input);
+
+    //then
+    assertThat(actualResult).isNotNull()
+        .hasSize(3)
+        .contains(
+            new Race(7, 9),
+            new Race(15, 40),
+            new Race(30, 200)
+        );
+  }
+
+  @ParameterizedTest
+  @CsvSource({
+      "0,0",
+      "1,6",
+      "2,10",
+      "3,12",
+      "4,12",
+      "5,10",
+      "6,6",
+      "7,0"
+  })
+  void canCalculateDistance(int durationOfButton, int expectedDistance) {
+    //given
+    var durationOfRace = 7;
+
+    //when
+    var actualResult = WaitForItPartOne.calculateDistance(durationOfButton, durationOfRace);
+
+    //then
+    assertThat(actualResult).isEqualTo(expectedDistance);
+  }
+
+  @Test
+  void canGenerateNumberOfPossibleWins(){
+    //given
+    var input = """
+        Time:      7  15   30
+        Distance:  9  40  200
+        """;
+
+    //when
+    var actualResult = WaitForItPartOne.generateNumberOfWays(input);
+
+    //then
+    assertThat(actualResult).isEqualTo(288);
+  }
+
+}