Feat: 207. Course Schedule

Author: HC-kang

course-schedule/HC-kang.ts

@@ -0,0 +1,34 @@
+/**
+ * https://leetcode.com/problems/course-schedule/
+ * T.C. O(V + E)
+ * S.C. O(V + E)
+ */
+function canFinish(numCourses: number, prerequisites: number[][]): boolean {
+  const graph: number[][] = Array.from({ length: numCourses }, () => []);
+  for (const [course, pre] of prerequisites) {
+    graph[pre].push(course);
+  }
+
+  const visited = new Array(numCourses).fill(false);
+  const visiting = new Array(numCourses).fill(false);
+
+  const dfs = (course: number): boolean => {
+    if (visited[course]) return true;
+    if (visiting[course]) return false;
+
+    visiting[course] = true;
+    for (const neighbor of graph[course]) {
+      if (!dfs(neighbor)) return false;
+    }
+    visiting[course] = false;
+    visited[course] = true;
+
+    return true;
+  };
+
+  for (let i = 0; i < numCourses; i++) {
+    if (!visited[i] && !dfs(i)) return false;
+  }
+
+  return true;
+}