hogwarts/courselist.go

@@ -2,6 +2,39 @@
 
 package hogwarts
 
-func GetCourseList(prereqs map[string][]string) []string {
-	return []string{}
+import (
+	"log"
+	"slices"
+)
+
+func singleCourseList(
+	course string, prereqs map[string][]string, list []string, traversed []string,
+) []string {
+	if slices.Contains(traversed, course) {
+		log.Panic("Recursive prereqs, aborting...")
+	}
+	traversed = append(traversed, course)
+	for _, prereqCourse := range prereqs[course] {
+		if !slices.Contains(list, prereqCourse) {
+			i := slices.Index(list, course)
+			if i == -1 {
+				list = append(list, prereqCourse)
+			} else {
+				list = slices.Insert(list, i, prereqCourse)
+			}
+		}
+		list = singleCourseList(prereqCourse, prereqs, list, traversed)
+	}
+	return list
+}
+
+func GetCourseList(prereqs map[string][]string) []string {
+	list := make([]string, 0)
+	for course := range prereqs {
+		if !slices.Contains(list, course) {
+			list = append(list, course)
+		}
+		list = singleCourseList(course, prereqs, list, []string{})
+	}
+	return list
 }