Solution for 2024, Day 19

2024/src/main/java/me/zodac/advent/Day19.java

@@ -0,0 +1,90 @@
+/*
+ * BSD Zero Clause License
+ *
+ * Copyright (c) 2021-2024 zodac.me
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+package me.zodac.advent;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Solution for 2024, Day 19.
+ *
+ * @see <a href="https://adventofcode.com/2024/day/19">[2024: 19] Linen Layout</a>
+ */
+public final class Day19 {
+
+    private Day19() {
+
+    }
+
+    /**
+     * Given a {@link List} of values (representing a final 'design'), and a {@link List} of keys (representing a single 'towel' which is part of the
+     * full design), find which values have a possible valid combination from the provided keys.
+     *
+     * @param towels       the input keys (towels to make the designs)
+     * @param finalDesigns the input values (designs)
+     * @return the number of valid designs that can be created
+     */
+    public static long countPossibleDesigns(final List<String> towels, final List<String> finalDesigns) {
+        return finalDesigns
+            .stream()
+            .filter(design -> hasDesignAnyValidCombinations(design, towels))
+            .count();
+    }
+
+    /**
+     * Given a {@link List} of values (representing a final 'design'), and a {@link List} of keys (representing a single 'towel' which is part of the
+     * full design), find which values have a possible valid combination from the provided keys. For each of these, find the total number of possible
+     * combinations of towels that can make the design.
+     *
+     * @param towels       the input keys (towels to make the designs)
+     * @param finalDesigns the input values (designs)
+     * @return the total number of towel combinations to create valid designs
+     */
+    public static long countAllCombinationsOfValidDesigns(final List<String> towels, final List<String> finalDesigns) {
+        return finalDesigns
+            .stream()
+            .filter(design -> hasDesignAnyValidCombinations(design, towels))
+            .mapToLong(design -> countCombinationsForDesign(design, towels, new HashMap<>()))
+            .sum();
+    }
+
+    private static boolean hasDesignAnyValidCombinations(final String value, final List<String> keys) {
+        return keys
+            .stream()
+            .anyMatch(key -> value.equals(key) || (value.startsWith(key) && hasDesignAnyValidCombinations(value.substring(key.length()), keys)));
+    }
+
+    private static long countCombinationsForDesign(final String design, final List<String> towels, final Map<String, Long> cache) {
+        if (cache.containsKey(design)) {
+            return cache.get(design);
+        }
+
+        long numberOfCombinations = 0L;
+        for (final String towel : towels) {
+            if (design.equals(towel)) {
+                numberOfCombinations++;
+            } else if (design.startsWith(towel)) {
+                numberOfCombinations += countCombinationsForDesign(design.substring(towel.length()), towels, cache);
+            }
+        }
+
+        cache.put(design, numberOfCombinations);
+        return numberOfCombinations;
+    }
+}

2024/src/test/java/me/zodac/advent/Day19Test.java

@@ -0,0 +1,92 @@
+/*
+ * BSD Zero Clause License
+ *
+ * Copyright (c) 2021-2024 zodac.me
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+package me.zodac.advent;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+import me.zodac.advent.input.InputReader;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests to verify answers for {@link Day19}.
+ */
+class Day19Test {
+
+    private static final String INPUT_FILENAME = "day19.txt";
+
+    @Test
+    void example() {
+        final List<List<String>> valuesRaw = InputReader
+            .forExample(INPUT_FILENAME)
+            .asStrings()
+            .grouped()
+            .byDelimiter(String::isBlank);
+
+        final List<String> keys = parseKeys(valuesRaw);
+        final List<String> values = valuesRaw.getLast();
+
+        final long part1Result = Day19.countPossibleDesigns(keys, values);
+        assertThat(part1Result)
+            .isEqualTo(6L);
+
+        final long part2Result = Day19.countAllCombinationsOfValidDesigns(keys, values);
+        assertThat(part2Result)
+            .isEqualTo(16L);
+    }
+
+    @Test
+    void part1() {
+        final List<List<String>> valuesRaw = InputReader
+            .forPuzzle(INPUT_FILENAME)
+            .asStrings()
+            .grouped()
+            .byDelimiter(String::isBlank);
+
+        final List<String> keys = parseKeys(valuesRaw);
+        final List<String> values = valuesRaw.getLast();
+
+        final long part1Result = Day19.countPossibleDesigns(keys, values);
+        assertThat(part1Result)
+            .isEqualTo(263L);
+    }
+
+    @Test
+    void part2() {
+        final List<List<String>> valuesRaw = InputReader
+            .forPuzzle(INPUT_FILENAME)
+            .asStrings()
+            .grouped()
+            .byDelimiter(String::isBlank);
+
+        final List<String> keys = parseKeys(valuesRaw);
+        final List<String> values = valuesRaw.getLast();
+
+        final long part2Result = Day19.countAllCombinationsOfValidDesigns(keys, values);
+        assertThat(part2Result)
+            .isEqualTo(723_524_534_506_343L);
+    }
+
+    private static List<String> parseKeys(List<List<String>> valuesRaw) {
+        final String[] keys = valuesRaw.getFirst().getFirst().split(", ");
+        return new ArrayList<>(Arrays.asList(keys)).stream().sorted(Comparator.comparingInt(String::length).reversed()).toList();
+    }
+}

2024/src/test/resources/day19.txt

@@ -0,0 +1,10 @@
+r, wr, b, g, bwu, rb, gb, br
+
+brwrr
+bggr
+gbbr
+rrbgbr
+ubwu
+bwurrg
+brgr
+bbrgwb

README.md

@@ -1,6 +1,6 @@
 # Advent Of Code: Java Edition
 
-![2024](https://img.shields.io/badge/2024%20⭐-30-yellow)
+![2024](https://img.shields.io/badge/2024%20⭐-32-yellow)
 ![2023](https://img.shields.io/badge/2023%20⭐-32-yellow)
 ![2022](https://img.shields.io/badge/2022%20⭐-28-yellow)
 ![2021](https://img.shields.io/badge/2021%20⭐-19-orange)
@@ -76,6 +76,7 @@ The source code is released under the [BSD Zero Clause License](https://opensour
 | [Day 16](https://adventofcode.com/2024/day/16) |          |          |
 | [Day 17](https://adventofcode.com/2024/day/17) |          |          |
 | [Day 18](https://adventofcode.com/2024/day/18) | 22,587 ⭐ | 21,997 ⭐ |
+| [Day 19](https://adventofcode.com/2024/day/19) |  7,778 ⭐ |  6,372 ⭐ |
 
 </details>
 

create.sh

@@ -102,11 +102,11 @@ function main() {
     fi
 
     echo "${output}" | head -n -1 > "./advent-of-code-inputs/${year}/day${day_long}.txt" || exit 1
-    cd ./advent-of-code-inputs || exit 1
-    git add "${year}/day${day_long}.txt"
-    git commit --quiet -m "Adding input for ${year}, Day ${day_long}"
-    git push origin HEAD:main --quiet
-    cd .. || exit 1
+#    cd ./advent-of-code-inputs || exit 1
+#    git add "${year}/day${day_long}.txt"
+#    git commit --quiet -m "Adding input for ${year}, Day ${day_long}"
+#    git push origin HEAD:main --quiet
+#    cd .. || exit 1
   fi
 
   # Example input file