Day 3-6 2019

2020-12-31 00:01:58 +01:00
parent 4fef41464e
commit ae327a4928
14 changed files with 1472 additions and 15 deletions
@@ -0,0 +1,81 @@
+package be.vandewalleh.aoc;
+
+import be.vandewalleh.aoc.utils.factory.Days;
+import be.vandewalleh.aoc.utils.input.Day;
+import be.vandewalleh.aoc.utils.input.Input;
+import be.vandewalleh.aoc.utils.input.Text;
+
+import java.util.Arrays;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+@Day(4)
+public class Day04 {
+
+    public static void main(String[] args) {
+        var day = Days.createDay(Day04.class);
+        System.out.println(day.part1());
+        System.out.println(day.part2());
+    }
+
+    private final int min;
+    private final int max;
+
+    public Day04(@Text Input<String> input) {
+        var spl = input.getValue().split("-", 2);
+        min = Integer.parseInt(spl[0]);
+        max = Integer.parseInt(spl[1]);
+    }
+
+    private boolean isNotDecreasing(int[] ints) {
+        for (int i = 0; i < 5; i++) {
+            int a = ints[i], b = ints[i + 1];
+            if (b < a) return false;
+        }
+        return true;
+    }
+
+    private boolean hasPair(int[] ints) {
+        for (int i = 0; i < 5; i++) {
+            int a = ints[i], b = ints[i + 1];
+            if (a == b) return true;
+        }
+        return false;
+    }
+
+    private boolean hasGroup(int[] ints) {
+        var occurrences = new int[10];
+        for (int i = 0; i < 5; i++) {
+            int a = ints[i], b = ints[i + 1];
+            if (a == b) occurrences[a]++;
+        }
+        return Arrays.stream(occurrences).anyMatch(e -> e == 1);
+    }
+
+    private Stream<int[]> intStream() {
+        return IntStream.rangeClosed(min, max)
+            .mapToObj(String::valueOf)
+            .map(String::toCharArray)
+            .map(e -> {
+                var ints = new int[6];
+                for (int i = 0; i < 6; i++) {
+                    ints[i] = Integer.parseInt(String.valueOf(e[i]));
+                }
+                return ints;
+            });
+    }
+
+    private long part1() {
+        return intStream()
+            .filter(this::isNotDecreasing)
+            .filter(this::hasPair)
+            .count();
+    }
+
+    private long part2() {
+        return intStream()
+            .filter(this::isNotDecreasing)
+            .filter(this::hasGroup)
+            .count();
+    }
+}