day04 for AoC 2023 (part 1)

Took 22 minutes

Author: albertominetti

src/main/java/aminetti/adventofcode2024/day04/Day04.java

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+package aminetti.adventofcode2024.day04;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.List;
+
+public class Day04 {
+    private static final Logger LOGGER = LoggerFactory.getLogger(Day04.class);
+    private List<String> input;
+    private int ROWS;
+    private int COLS;
+
+    public Day04() {
+    }
+
+    public void parseInput(List<String> input) {
+        this.input = input;
+
+        ROWS = input.size();
+        COLS = input.getFirst().length();
+    }
+
+    public long solvePart1() {
+        long sum = 0;
+        for (int i = 0; i < input.size(); i++) {
+            String l = input.get(i);
+            for (int j = 0; j < l.length(); j++) {
+                char c = l.charAt(j);
+                if (c == 'X') {
+                    sum += countXmas(i, j);
+                }
+            }
+        }
+        return sum;
+    }
+
+    private long countXmas(int i, int j) {
+        long count = 0;
+
+        // NW, SW, SE, NE
+        count += lookingFor("MAS", i - 1, j - 1, -1, -1);
+        count += lookingFor("MAS", i + 1, j + 1, +1, +1);
+        count += lookingFor("MAS", i - 1, j + 1, -1, +1);
+        count += lookingFor("MAS", i + 1, j - 1, +1, -1);
+
+        // N, S, W, O
+        count += lookingFor("MAS", i - 1, j, -1, 0);
+        count += lookingFor("MAS", i + 1, j , +1, 0);
+        count += lookingFor("MAS", i , j + 1, 0, +1);
+        count += lookingFor("MAS", i , j - 1, 0, -1);
+
+        return count;
+    }
+
+    private long lookingFor(String search, int i, int j, int dirI, int dirJ) {
+        if (search.isEmpty()) {
+            return 1;
+        }
+        if (i < 0 || i >= ROWS || j < 0 || j >= COLS) {
+            return 0;
+        }
+        LOGGER.info("Index {} and {}", i, j);
+        if (search.charAt(0) == input.get(i).charAt(j)) {
+            return lookingFor(search.substring(1), i + dirI, j + dirJ, dirI, dirJ);
+        }
+
+        return 0;
+    }
+
+    public long solvePart2() {
+
+        return 0;
+    }
+}

src/test/java/aminetti/adventofcode2024/day04/Day04Test.java

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+package aminetti.adventofcode2024.day04;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.util.List;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.apache.commons.io.IOUtils.readLines;
+import static org.apache.commons.io.IOUtils.resourceToString;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+
+class Day04Test {
+
+    @Test
+    void actualInputPart1() throws IOException {
+        // given
+        List<String> input = readLines(resourceToString("/day04/day04_input.txt", UTF_8));
+
+        // when
+        Day04 solver = new Day04();
+        solver.parseInput(input);
+        long l = solver.solvePart1();
+
+        // then
+        assertThat(l, is(2599L));
+    }
+
+    @Test
+    void testInputPart1() throws IOException {
+        // given
+        List<String> input = readLines(resourceToString("/day04/day04_input_test.txt", UTF_8));
+
+        // when
+        Day04 solver = new Day04();
+        solver.parseInput(input);
+        long l = solver.solvePart1();
+
+        // then
+        assertThat(l, is(18L));
+    }
+
+    @Test
+    void actualInputPart2() throws IOException {
+        // given
+        List<String> input = readLines(resourceToString("/day04/day04_input.txt", UTF_8));
+
+        // when
+        Day04 solver = new Day04();
+        solver.parseInput(input);
+        long l = solver.solvePart2();
+
+        // then
+        assertThat(l, is(0L));
+    }
+
+    @Test
+    void testInputPart2() throws IOException {
+        // given
+        List<String> input = readLines(resourceToString("/day04/day04_input_test.txt", UTF_8));
+
+        // when
+        Day04 solver = new Day04();
+        solver.parseInput(input);
+        long l = solver.solvePart2();
+
+        // then
+        assertThat(l, is(0L));
+    }
+
+
+}

src/test/resources/day04/day04_input_test.txt

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+MMMSXXMASM
+MSAMXMSMSA
+AMXSXMAAMM
+MSAMASMSMX
+XMASAMXAMM
+XXAMMXXAMA
+SMSMSASXSS
+SAXAMASAAA
+MAMMMXMMMM
+MXMXAXMASX