Count components correctly

Fix a bug where if you placed a subcircuit twice, its contents were only
counted once. Going to try not to think about how long this has been broken.

README.md

@@ -372,6 +372,10 @@ it alongside a grader. The following steps are an example workflow:
     ...
     // version gitVersion()
     ```
+    For autograders (consumers) using newer versions of Gradle, you may also
+    need to comment out the `sourcesJar` and `javadocJar` tasks as well as the
+    `artifacts {}` and `publishing {}` sections. Isn't software "engineering"
+    fun?
  4. Run `./gradlew jar` in both the cloned copy of this repository and
     in the top-level autograder directory, in that order. If you modify
     the code in the copy of this repository, you will have to rerun the

src/main/java/io/zucchini/circuitsimtester/api/Subcircuit.java

@@ -264,7 +264,7 @@ public Map<String, Integer> lookupComponentCounts(
                         Map.Entry::getKey, entry -> entry.getValue().size()));
     }
 
-    private Map<String, Set<ComponentPeer<?>>> lookupComponentPeers(
+    private Map<String, List<ComponentPeer<?>>> lookupComponentPeers(
             Collection<String> componentNames,
             boolean inverse,
             boolean recursive) {
@@ -285,18 +285,19 @@ private Map<String, Set<ComponentPeer<?>>> lookupComponentPeers(
                 String.join(", ", components)));
         }
 
-        Map<String, Set<ComponentPeer<?>>> matchingComponents = new HashMap<>();
+        Map<String, List<ComponentPeer<?>>> matchingComponents = new HashMap<>();
         // Run a depth-first search through the simulation DAG starting
-        // at this subcircuit. (Setting revisit=false makes this a DFS)
-        walk(recursive, false, (circuitBoard, component) -> {
+        // at this subcircuit. Setting revisit=true ensures we correctly count the
+        // components in multiple occurrences of the same subcircuit
+        walk(recursive, true, (circuitBoard, component) -> {
             Pair<String, String> name = componentNameInfo.getPeerCategoryAndName(component);
             boolean match = goalCategories.contains(name.getKey()) ||
                             goalComponents.contains(name.getValue());
 
             if (match ^ inverse) {
                 matchingComponents.computeIfAbsent(
                     name.getValue(),
-                    k -> new HashSet<>()).add(component);
+                    k -> new ArrayList<>()).add(component);
             }
         });