Add week 9 solutions: courseSchedule

Author: yolophg

course-schedule/yolophg.js

@@ -0,0 +1,47 @@
+// Time Complexity: O(m * n)
+// Space Complexity: O(m * n)
+
+// initialize an array to keep track of the in-degrees for each course
+let inDegree = new Array(numCourses).fill(0);
+// initialize an adjacency list to represent the graph of courses
+let adjList = new Array(numCourses).fill(0).map(() => []);
+
+// fill the in-degree array and adjacency list based on the prerequisites
+for (let [course, prereq] of prerequisites) {
+  // increment the in-degree of the course
+  inDegree[course]++;
+  // add the course to the adjacency list of the prerequisite
+  adjList[prereq].push(course);
+}
+
+// initialize a queue to keep track of courses with no prerequisites (in-degree of 0)
+let queue = [];
+for (let i = 0; i < numCourses; i++) {
+  if (inDegree[i] === 0) {
+    queue.push(i);
+  }
+}
+
+// initialize a counter to keep track of the number of courses that have been processed
+let count = 0;
+
+// process the courses with no prerequisites
+while (queue.length > 0) {
+  // get a course from the queue
+  let current = queue.shift();
+  // increment the counter as this course can be taken
+  count++;
+
+  // iterate through the adjacency list of the current course
+  for (let neighbor of adjList[current]) {
+    // decrement the in-degree of the neighboring course
+    inDegree[neighbor]--;
+    // if in-degree becomes 0, add it to the queue
+    if (inDegree[neighbor] === 0) {
+      queue.push(neighbor);
+    }
+  }
+}
+
+// if the count of processed courses equals the total number of courses, return true
+return count === numCourses;