course schedule solution

Author: hyer0705

course-schedule/hyer0705.ts

@@ -0,0 +1,34 @@
+function canFinish(numCourses: number, prerequisites: number[][]): boolean {
+  const graph: number[][] = Array.from({ length: numCourses }, () => []);
+  const inDegree: number[] = Array(numCourses).fill(0);
+
+  for (const [course, prerequisite] of prerequisites) {
+    graph[prerequisite].push(course);
+    inDegree[course]++;
+  }
+
+  // 지금 당장 수강할 수 있는 과목 목록
+  const queue: number[] = [];
+
+  for (let i = 0; i < numCourses; i++) {
+    if (inDegree[i] === 0) {
+      queue.push(i);
+    }
+  }
+
+  const result: number[] = [];
+  while (queue.length > 0) {
+    const course = queue.shift()!;
+    result.push(course);
+
+    for (const nextCourse of graph[course]) {
+      inDegree[nextCourse]--;
+      if (inDegree[nextCourse] === 0) {
+        queue.push(nextCourse);
+      }
+    }
+  }
+
+  if (result.length !== numCourses) return false;
+  return true;
+}