Day 1

l0s · l0s · commit db781d62e5eb · 2021-11-30T21:37:21.000-08:00
diff --git a/.gitignore b/.gitignore
@@ -4,3 +4,6 @@
 .settings
 advent-of-code.iml
 target/
+src/test/resources/config.properties
+src/test/resources/input
+src/test/resources/2020
diff --git a/src/test/java/com/macasaet/Day01.java b/src/test/java/com/macasaet/Day01.java
@@ -1,25 +1,65 @@
 package com.macasaet;
 
-import java.util.stream.Stream;
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
 import java.util.stream.StreamSupport;
 
 import org.junit.jupiter.api.Test;
 
-
+/**
+ * --- Day 1: Sonar Sweep ---
+ */
 public class Day01 {
 
-    protected Stream<String> getInput() {
-        return StreamSupport.stream(new LineSpliterator(getClass().getResourceAsStream("/day-1-input.txt")),
-                false);
+    /**
+     * Perform a sonar sweep of the nearby sea floor.
+     *
+     * @return measurements of the sea floor depth further and further away from the submarine
+     */
+    protected List<Integer> getInput() {
+        return StreamSupport
+                .stream(new LineSpliterator("day-01.txt"),
+                        false)
+                .mapToInt(Integer::parseInt)
+                .collect(ArrayList::new, List::add, List::addAll);
     }
 
     @Test
     public final void part1() {
-
+        final var list = getInput();
+        int increases = countIncreases(list);
+        System.out.println("Part 1: " + increases);
     }
 
     @Test
     public final void part2() {
+        final var list = getInput();
+        final var windows = new LinkedList<Integer>();
+        for (int i = 2; i < list.size(); i++) {
+            windows.add(list.get(i) + list.get(i - 1) + list.get(i - 2));
+        }
+        final int increases = countIncreases(windows);
+        System.out.println("Part 2: " + increases);
+    }
 
+    /**
+     * Determine how quickly the depth increases.
+     *
+     * @param list progressively further measurements of the sea floor depth
+     * @return the number of times a depth measurement increase from the previous measurement
+     */
+    protected int countIncreases(final List<? extends Integer> list) {
+        int previous = list.get(0);
+        int increases = 0;
+        for (int i = 1; i < list.size(); i++) {
+            final var current = list.get(i);
+            if (current > previous) {
+                increases++;
+            }
+            previous = current;
+        }
+        return increases;
     }
-}
+
+}
diff --git a/src/test/java/com/macasaet/LineSpliterator.java b/src/test/java/com/macasaet/LineSpliterator.java
@@ -1,18 +1,26 @@
 package com.macasaet;
 
-import java.io.BufferedReader;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.io.Reader;
+import java.io.*;
 import java.util.Objects;
+import java.util.Properties;
 import java.util.Spliterator;
 import java.util.function.Consumer;
 
 public class LineSpliterator implements Spliterator<String>, AutoCloseable {
 
+    private static final String prefix;
     private final BufferedReader reader;
 
+    static {
+        final var properties = new Properties();
+        try {
+            final var config = LineSpliterator.class.getResourceAsStream("/config.properties");
+            if (config != null) properties.load(config);
+        } catch (final IOException ignored) {
+        }
+        prefix = properties.getProperty("prefix", "/sample");
+    }
+
     public LineSpliterator(final BufferedReader reader) {
         Objects.requireNonNull(reader);
         this.reader = reader;
@@ -26,6 +34,10 @@ public LineSpliterator(final InputStream stream) {
         this(new InputStreamReader(stream));
     }
 
+    public LineSpliterator(final String fileName) {
+        this(LineSpliterator.class.getResourceAsStream(prefix + "/" + fileName));
+    }
+
     public boolean tryAdvance(final Consumer<? super String> action) {
         try {
             final var line = reader.readLine();
diff --git a/src/test/resources/sample/day-01.txt b/src/test/resources/sample/day-01.txt
@@ -0,0 +1,10 @@
+199
+200
+208
+210
+200
+207
+240
+269
+260
+263

-Original file line number
+Diff line change
@@ @@ -0,0 +1,10 @@ @@
 +199
 +200
 +208
 +210
 +200
 +207
 +240
 +269
 +260
 +263