Added courseSchedule solution

Author: nhistory

course-schedule/nhistory.js

@@ -0,0 +1,49 @@
+/**
+ * @param {number} numCourses
+ * @param {number[][]} prerequisites
+ * @return {boolean}
+ */
+var canFinish = function (numCourses, prerequisites) {
+  // Initialize in-degree array and graph map
+  const inDegree = Array(numCourses).fill(0);
+  const graph = new Map();
+
+  // Build the graph and compute in-degrees
+  prerequisites.forEach(([course, pre]) => {
+    inDegree[course]++;
+    if (!graph.has(pre)) {
+      graph.set(pre, []);
+    }
+    graph.get(pre).push(course);
+  });
+
+  // Queue for courses with no prerequisites
+  const queue = [];
+  for (let i = 0; i < numCourses; i++) {
+    if (inDegree[i] === 0) {
+      queue.push(i);
+    }
+  }
+
+  // Process the courses
+  let count = 0;
+  while (queue.length > 0) {
+    const course = queue.shift();
+    count++;
+    if (graph.has(course)) {
+      graph.get(course).forEach((nextCourse) => {
+        inDegree[nextCourse]--;
+        if (inDegree[nextCourse] === 0) {
+          queue.push(nextCourse);
+        }
+      });
+    }
+  }
+
+  // Return true if all courses can be finished
+  return count === numCourses;
+};
+
+// TC: O(V + E)
+// V is the number of courses, E is the number of prerequisites.
+// SC: O(V + E)