Add 207_Course_Schedule.java

Author: Sean Prashad

Topological Sort/.gitkeep

@@ -0,0 +1,35 @@
+class Solution {
+ public boolean canFinish(int numCourses, int[][] prerequisites) {
+ List<Integer>[] adjList = new ArrayList[numCourses];
+ int[] indegrees = new int[numCourses];
+ Queue<Integer> q = new LinkedList<>();
+ int courseCount = 0;
+
+ for (int i = 0; i < numCourses; i++) {
+ adjList[i] = new ArrayList<>();
+ }
+ for (int[] pair : prerequisites) {
+ adjList[pair[1]].add(pair[0]);
+ ++indegrees[pair[0]];
+ }
+
+ for (int i = 0; i < indegrees.length; i++) {
+ if (indegrees[i] == 0) {
+ q.offer(i);
+ }
+ }
+
+ while (!q.isEmpty()) {
+ int course = q.poll();
+ ++courseCount;
+
+ for (int prereqCourse : adjList[course]) {
+ if (--indegrees[prereqCourse] == 0) {
+ q.offer(prereqCourse);
+ }
+ }
+ }
+
+ return courseCount == numCourses;
+ }
+}