feat: ✨ Day 01-02 (WIP)

.github/workflows/build.yml

@@ -0,0 +1,27 @@
+name: Build and Test
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Set up JDK 21
+      uses: actions/setup-java@v4
+      with:
+        distribution: 'temurin'
+        java-version: '21'
+        cache: maven
+
+    - name: Check formatting
+      run: mvn spotless:check
+
+    - name: Build with Maven
+      run: mvn -B package --file pom.xml

.gitignore

@@ -0,0 +1,33 @@
+HELP.md
+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/

README.md

@@ -1 +1,38 @@
-# advent-of-code-2024
+# Advent of Code 2024
+
+[![Build and Test](https://github.com/edwinhern/advent-of-code-2024/actions/workflows/build.yml/badge.svg)](https://github.com/edwinhern/advent-of-code-2024/actions/workflows/build.yml)
+
+My solutions for [Advent of Code 2024](https://adventofcode.com/2024) implemented in Java.
+
+## Project Structure
+
+- `src/main/java/dayXX` - Contains solution for each day
+- `src/main/resources/dayXX` - Contains input files for each day's puzzle
+
+## Running Solutions
+
+This is a Maven project. To run:
+
+1. Clone the repository
+2. Build the project: `mvn clean package`
+3. Run individual day solutions through their respective main methods
+
+## Development
+
+- Java 17
+- Maven for build management
+- Spotless for code formatting
+
+### Code Formatting
+
+Format code before committing:
+
+```bash
+mvn spotless:apply
+```
+
+## Progress
+
+- [x] Day 1
+- [x] Day 2
+- [ ] Day 3-25 (Coming Soon)

pom.xml

@@ -44,6 +44,27 @@
                 <artifactId>maven-surefire-plugin</artifactId>
                 <version>3.0.0</version>
             </plugin>
+
+            <plugin>
+                <groupId>com.diffplug.spotless</groupId>
+                <artifactId>spotless-maven-plugin</artifactId>
+                <version>2.41.1</version>
+                <configuration>
+                    <java>
+                        <googleJavaFormat>
+                            <version>1.17.0</version>
+                            <style>GOOGLE</style>
+                        </googleJavaFormat>
+                    </java>
+                </configuration>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>check</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
         </plugins>
     </build>
 </project>

src/main/java/day01/Day01.java

@@ -2,51 +2,66 @@
 
 import java.io.FileReader;
 import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.Path;
 import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
-
-import com.opencsv.CSVReader;
-import com.opencsv.exceptions.CsvValidationException;
+import java.util.Map;
+import java.util.Scanner;
+import java.util.logging.Logger;
 
 public class Day01 {
+  private static final Logger LOGGER = Logger.getLogger(Day01.class.getName());
+
+  public static void main(String[] args) throws IOException {
+    List<Integer> left = new ArrayList<>();
+    List<Integer> right = new ArrayList<>();
 
-  public static void main(String[] args) throws IOException, CsvValidationException {
-    // read through the csv file
-    // iterate and create left and right list
-    List<List<String>> records = new ArrayList<>();
-    try (CSVReader csvReader = new CSVReader(new FileReader("src/main/resources/day01/input.csv"))) {
-      String[] values = null;
-      while ((values = csvReader.readNext()) != null) {
-        records.add(Arrays.asList(values));
+    try (Scanner scanner = new Scanner(new FileReader("src/main/resources/day01/input.txt"))) {
+      while (scanner.hasNextLine()) {
+        String line = scanner.nextLine();
+        Scanner lineScanner = new Scanner(line);
+        lineScanner.useDelimiter("   ");
+        left.add(lineScanner.nextInt());
+        right.add(lineScanner.nextInt());
+
+        lineScanner.close();
       }
     }
 
-    List<Integer> left = new ArrayList<>();
-    List<Integer> right = new ArrayList<>();
+    // Part 1: Calculate total distance between sorted lists
+    LOGGER.info(() -> "Part 1 Solution: " + part1(left, right));
 
-    for (List<String> record : records) {
-      left.add(Integer.parseInt(record.get(0)));
-      right.add(Integer.parseInt(record.get(1)));
+    // Part 2: Calculate similarity score
+    LOGGER.info(() -> "Part 2 Solution: " + part2(left, right));
+  }
+
+  private static int part1(List<Integer> left, List<Integer> right) {
+    List<Integer> sortedLeft = new ArrayList<>(left);
+    List<Integer> sortedRight = new ArrayList<>(right);
+    sortedLeft.sort(Integer::compareTo);
+    sortedRight.sort(Integer::compareTo);
+
+    int totalDistance = 0;
+    for (int i = 0; i < sortedLeft.size(); i++) {
+      totalDistance += Math.abs(sortedLeft.get(i) - sortedRight.get(i));
     }
 
-    // take first list and sort in asc
-    // take second list and sort in asc
-    Collections.sort(left);
-    Collections.sort(right);
-
-    // create sum variable to hold difference
-    int sum = 0;
-    // iterate through first list
-    for (int i = 0; i < left.size(); i++) {
-      // access left and right based on i
-      // sum += Math.abs(left[i] - right[i])
-      sum += Math.abs(left.get(i) - right.get(i));
+    return totalDistance;
+  }
+
+  private static int part2(List<Integer> left, List<Integer> right) {
+    Map<Integer, Integer> rightMap = new HashMap<>();
+    for (int num : right) {
+      rightMap.merge(num, 1, Integer::sum);
+    }
+
+    int similarityScore = 0;
+    for (int num : left) {
+      if (rightMap.containsKey(num)) {
+        similarityScore += num * rightMap.getOrDefault(num, 0);
+      }
     }
 
-    System.out.println(sum);
+    return similarityScore;
   }
 }

src/main/java/day02/Day02.java

@@ -0,0 +1,51 @@
+package day02;
+
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Scanner;
+import java.util.logging.Logger;
+import java.util.stream.Collectors;
+
+public class Day02 {
+  private static final Logger LOGGER = Logger.getLogger(Day02.class.getName());
+
+  public static void main(String[] args) throws IOException {
+    List<List<Integer>> reports = new ArrayList<>();
+
+    try (Scanner scanner = new Scanner(new FileReader("src/main/resources/day02/input.txt"))) {
+      while (scanner.hasNextLine()) {
+        String line = scanner.nextLine();
+        List<Integer> levels =
+            Arrays.stream(line.split(" ")).map(Integer::parseInt).collect(Collectors.toList());
+
+        reports.add(levels);
+      }
+    }
+
+    LOGGER.info(() -> "Part 1 Solution: " + part1(reports));
+  }
+
+  private static int part1(List<List<Integer>> reports) {
+    return (int) reports.stream().filter(Day02::isSafeReport).count();
+  }
+
+  private static boolean isSafeReport(List<Integer> levels) {
+    boolean isIncreasing = levels.get(1) > levels.get(0);
+
+    for (int i = 1; i < levels.size(); i++) {
+      int diff = levels.get(i) - levels.get(i - 1);
+
+      // Validate if diff is within bounds (1-3) or if it's increasing or decreasing
+      boolean isWithinBounds = diff == 0 || Math.abs(diff) > 3;
+      boolean isIncreasingBounds = isIncreasing && diff < 0;
+      boolean isDecreasingBounds = !isIncreasing && diff > 0;
+      if (isWithinBounds || isIncreasingBounds || isDecreasingBounds) {
+        return false;
+      }
+    }
+    return true;
+  }
+}