Added Day 5 of 2015

src/main/java/com/belellou/kevin/advent/year2015/Day5.java

@@ -0,0 +1,106 @@
+package com.belellou.kevin.advent.year2015;
+
+import java.io.BufferedReader;
+import java.util.HashSet;
+import java.util.Set;
+
+import com.belellou.kevin.advent.generic.AbstractDaySolver;
+import com.belellou.kevin.advent.generic.Day;
+import com.belellou.kevin.advent.generic.Year;
+
+@SuppressWarnings("unused")
+public class Day5 extends AbstractDaySolver {
+
+    public Day5() {
+        super(Year.YEAR_2015, Day.DAY_5);
+    }
+
+    private static boolean firstStarStringTest(String string) {
+        int vowelCount = 0;
+        char lastChar = '0';
+        boolean foundDouble = false;
+
+        Set<Character> vowels = Set.of('a', 'e', 'i', 'o', 'u');
+        Set<String> forbidden = Set.of("ab", "cd", "pq", "xy");
+
+        for (int i = 0; i < string.length(); i++) {
+            char c = string.charAt(i);
+
+            if (forbidden.contains(lastChar + String.valueOf(c))) {
+                return false;
+            }
+
+            if (vowels.contains(c)) {
+                vowelCount++;
+            }
+
+            if (lastChar == c) {
+                foundDouble = true;
+            }
+
+            lastChar = c;
+        }
+
+        return foundDouble && vowelCount >= 3;
+    }
+
+    private static boolean secondStarStringTest(String string) {
+        char lastChar = '0';
+        char lastLastChar = '0';
+
+        Set<String> pairs = new HashSet<>();
+        boolean foundPair = false;
+        boolean lastPairWasDouble = false;
+
+        boolean foundTrio = false;
+
+        for (int i = 0; i < string.length(); i++) {
+            char c = string.charAt(i);
+
+            String pair = lastChar + String.valueOf(c);
+
+            if (pairs.contains(pair) && !(lastPairWasDouble && lastChar == c)) {
+                foundPair = true;
+            }
+
+            if (lastLastChar == c) {
+                foundTrio = true;
+            }
+
+            if (foundPair && foundTrio) {
+                return true;
+            }
+
+            if (i >= 1) {
+                pairs.add(pair);
+            }
+
+            lastPairWasDouble = !lastPairWasDouble && lastChar == c;
+
+            lastLastChar = lastChar;
+            lastChar = c;
+        }
+
+        return false;
+    }
+
+    @Override
+    protected int doSolveFirstStar(BufferedReader reader) {
+        return reader.lines().filter(Day5::firstStarStringTest).toList().size();
+    }
+
+    @Override
+    public int getFirstStarSolution() {
+        return 255;
+    }
+
+    @Override
+    protected int doSolveSecondStar(BufferedReader reader) {
+        return reader.lines().filter(Day5::secondStarStringTest).toList().size();
+    }
+
+    @Override
+    public int getSecondStarSolution() {
+        return 55;
+    }
+}