java/2016/24: add solution for part 2

Author: saser

java/src/main/java/com/github/saser/adventofcode/year2016/day24/Day24.java

@@ -29,7 +29,7 @@ private static Result solve(Reader r, int part) {
         var keys = findKeys(grid);
         var start = findStart(grid, keys);
         var distances = findDistances(grid, keys);
-        var steps = collectKeys(start, keys, distances);
+        var steps = collectKeys(start, keys, distances, part == 2);
         return Result.ok(Integer.toString(steps));
     }
 
@@ -112,7 +112,7 @@ private static Map<Point2D, Map<Point2D, Integer>> findDistances(char[][] grid,
         return distances;
     }
 
-    private static int collectKeys(Point2D start, Set<Point2D> keys, Map<Point2D, Map<Point2D, Integer>> distances) {
+    private static int collectKeys(Point2D start, Set<Point2D> keys, Map<Point2D, Map<Point2D, Integer>> distances, boolean returnToStart) {
         var queue = new PriorityQueue<Tuple3<Point2D, Set<Point2D>, Integer>>(Comparator.comparing(tuple -> tuple.v3));
         queue.add(new Tuple3<>(start, Set.of(start), 0));
         var visited = new HashSet<Tuple2<Point2D, Set<Point2D>>>();
@@ -127,6 +127,9 @@ private static int collectKeys(Point2D start, Set<Point2D> keys, Map<Point2D, Ma
             }
             visited.add(state);
             if (collected.containsAll(keys)) {
+                if (returnToStart) {
+                    steps += distances.get(point).get(start);
+                }
                 return steps;
             }
             for (var entry : distances.get(point).entrySet()) {

java/src/test/java/com/github/saser/adventofcode/year2016/day24/Day24Test.java

@@ -27,22 +27,13 @@ public void part1Actual() throws IOException {
         }
     }
 
-    // @Test
-    // public void part2Example() {
-    //     var input = new StringReader("");
-    //     var output = "";
-    //     var result = Day24.part2(input);
-    //     Assert.assertEquals("no error", "", result.error);
-    //     Assert.assertEquals("correct output", output, result.answer);
-    // }
-
-    // @Test
-    // public void part2Actual() throws IOException {
-    //     try (var input = new FileReader("inputs/2016/24")) {
-    //         var output = "";
-    //         var result = Day24.part2(input);
-    //         Assert.assertEquals("no error", "", result.error);
-    //         Assert.assertEquals("correct output", output, result.answer);
-    //     }
-    // }
+     @Test
+     public void part2Actual() throws IOException {
+         try (var input = new FileReader("inputs/2016/24")) {
+             var output = "720";
+             var result = Day24.part2(input);
+             Assert.assertEquals("no error", "", result.error);
+             Assert.assertEquals("correct output", output, result.answer);
+         }
+     }
 }