From d8ddcbdd216875c1e1b742592a4e28411b4663a1 Mon Sep 17 00:00:00 2001
From: erius <egor_kapralov2003@mail.ru>
Date: Mon, 3 Jun 2024 02:06:06 +0300
Subject: [PATCH] Implemented hogwarts

---
 hogwarts/courselist.go | 37 +++++++++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/hogwarts/courselist.go b/hogwarts/courselist.go
index 34ea140..e2c947a 100644
--- a/hogwarts/courselist.go
+++ b/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
 }