Added 2016 Day 7

src/main/java/com/belellou/kevin/advent/year2016/Day7.java

@@ -0,0 +1,99 @@
+package com.belellou.kevin.advent.year2016;
+
+import java.io.BufferedReader;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.apache.commons.lang3.tuple.MutablePair;
+
+import com.belellou.kevin.advent.generic.AbstractDaySolver;
+
+@SuppressWarnings("unused")
+public class Day7 extends AbstractDaySolver<Integer> {
+
+    private static final char OPENING_BRACKET = '[';
+    private static final char CLOSING_BRACKET = ']';
+
+    public Day7() {
+        super(Day7.class);
+    }
+
+    private static boolean doesIpSupportTls(String ip) {
+        boolean hasAbba = false;
+        boolean isInHypernet = false;
+
+        for (int i = 3; i < ip.length(); i++) {
+            char c = ip.charAt(i);
+
+            if (c == OPENING_BRACKET) {
+                isInHypernet = true;
+            } else if (c == CLOSING_BRACKET) {
+                isInHypernet = false;
+            } else if (c == ip.charAt(i - 3) && c != ip.charAt(i - 2) && ip.charAt(i - 2) == ip.charAt(i - 1)) {
+                if (isInHypernet) {
+                    return false;
+                }
+                hasAbba = true;
+            }
+        }
+
+        return hasAbba;
+    }
+
+    private static boolean doesIpSupportSsl(String ip) {
+        Set<MutablePair<Character, Character>> abas = new HashSet<>();
+        Set<MutablePair<Character, Character>> babs = new HashSet<>();
+
+        boolean isInHypernet = false;
+
+        for (int i = 2; i < ip.length(); i++) {
+            char c = ip.charAt(i);
+
+            if (c == OPENING_BRACKET) {
+                isInHypernet = true;
+            } else if (c == CLOSING_BRACKET) {
+                isInHypernet = false;
+            } else if (c == ip.charAt(i - 2) && c != ip.charAt(i - 1)) {
+                if (isInHypernet) {
+                    MutablePair<Character, Character> pair = MutablePair.of(c, ip.charAt(i - 1));
+
+                    if (abas.contains(pair)) {
+                        return true;
+                    }
+
+                    babs.add(pair);
+                } else {
+                    MutablePair<Character, Character> pair = MutablePair.of(ip.charAt(i - 1), c);
+
+                    if (babs.contains(pair)) {
+                        return true;
+                    }
+
+                    abas.add(pair);
+                }
+            }
+        }
+
+        return false;
+    }
+
+    @Override
+    protected Integer doSolveFirstStar(BufferedReader reader) {
+        return Math.toIntExact(reader.lines().filter(Day7::doesIpSupportTls).count());
+    }
+
+    @Override
+    public Integer getFirstStarSolution() {
+        return 110;
+    }
+
+    @Override
+    protected Integer doSolveSecondStar(BufferedReader reader) {
+        return Math.toIntExact(reader.lines().filter(Day7::doesIpSupportSsl).count());
+    }
+
+    @Override
+    public Integer getSecondStarSolution() {
+        return 242;
+    }
+}