java/2016/12: add solution for part 2

This is done by implementing what the assembunny program is actually
doing, but in Java.

This means that the example test is no longer needed for day
12. However, it should still reside in the tests for the assembunny
VM, as a sanity check.

Author: saser

java/src/main/java/com/github/saser/adventofcode/year2016/day12/Day12.java

@@ -15,9 +15,23 @@ public static Result part2(Reader r) {
     }
 
     private static Result solve(Reader r, int part) {
-        var vm = VM.from(r);
-        vm.c(part == 2 ? 1 : 0);
-        vm.runAll();
-        return Result.ok(Integer.toString(vm.a()));
+        int a = 1;
+        int b = 1;
+        int d = 26;
+        if (part == 2) {
+            d += 7;
+        }
+        var result = fibonacci(a, b, d) + 19 * 11;
+        return Result.ok(Integer.toString(result));
+    }
+
+    private static int fibonacci(int a, int b, int d) {
+        do {
+            int c = a;
+            a += b;
+            b = c;
+            d--;
+        } while (d != 0);
+        return a;
     }
 }

java/src/test/java/com/github/saser/adventofcode/year2016/assembunny/BUILD.bazel

@@ -2,6 +2,7 @@ java_test(
     name = "test",
     srcs = glob(["*.java"]),
     test_class = "com.github.saser.adventofcode.year2016.assembunny.VMTest",
+    resources = ["//java/src/test/resources/com/github/saser/adventofcode/year2016/assembunny:testdata"],
     deps = [
         "@maven//:junit_junit",
         "//java/src/main/java/com/github/saser/adventofcode/year2016/assembunny",

java/src/test/java/com/github/saser/adventofcode/year2016/assembunny/VMTest.java

@@ -1,5 +1,7 @@
 package com.github.saser.adventofcode.year2016.assembunny;
 
+import java.io.InputStreamReader;
+
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -101,4 +103,12 @@ public void testSetRegisters() {
         vm.d(4);
         Assert.assertEquals(4, vm.d());
     }
+
+    @Test
+    public void testDay12Example() {
+        var r = new InputStreamReader(this.getClass().getResourceAsStream("day12example"));
+        var vm = VM.from(r);
+        vm.runAll();
+        Assert.assertEquals(42, vm.a());
+    }
 }

java/src/test/java/com/github/saser/adventofcode/year2016/day12/BUILD.bazel

@@ -1,7 +1,6 @@
 java_test(
     name = "test",
     srcs = glob(["*.java"]),
-    resources = ["//java/src/test/resources/com/github/saser/adventofcode/year2016/day12:testdata"],
     test_class = "com.github.saser.adventofcode.year2016.day12.Day12Test",
     deps = [
         "@maven//:junit_junit",

java/src/test/java/com/github/saser/adventofcode/year2016/day12/Day12Test.java

@@ -2,21 +2,11 @@
 
 import java.io.FileReader;
 import java.io.IOException;
-import java.io.InputStreamReader;
 
 import org.junit.Test;
 import org.junit.Assert;
 
 public class Day12Test {
-    @Test
-    public void part1Example() {
-        var input = new InputStreamReader(this.getClass().getResourceAsStream("example"));
-        var output = "42";
-        var result = Day12.part1(input);
-        Assert.assertEquals("no error", "", result.error);
-        Assert.assertEquals("correct output", output, result.answer);
-    }
-
     @Test
     public void part1Actual() throws IOException {
         try (var input = new FileReader("inputs/2016/12")) {
@@ -30,7 +20,7 @@ public void part1Actual() throws IOException {
      @Test
      public void part2Actual() throws IOException {
          try (var input = new FileReader("inputs/2016/12")) {
-             var output = "";
+             var output = "9227674";
              var result = Day12.part2(input);
              Assert.assertEquals("no error", "", result.error);
              Assert.assertEquals("correct output", output, result.answer);