| 1 | class Solution { |
| 2 | |
| 3 | public boolean canFinish(int numCourses, int[][] prerequisites) { |
| 4 | List<List<Integer>> adj = new ArrayList<>(); |
| 5 | for (int i = 0; i < numCourses; i++) { |
| 6 | adj.add(new ArrayList<>()); |
| 7 | } |
| 8 | |
| 9 | for (int i = 0; i < prerequisites.length; i++) { |
| 10 | adj.get(prerequisites[i][0]).add(prerequisites[i][1]); |
| 11 | } |
| 12 | |
| 13 | int[] visited = new int[numCourses]; |
| 14 | for (int i = 0; i < numCourses; i++) { |
| 15 | if (visited[i] == 0) { |
| 16 | if (isCyclic(adj, visited, i)) { |
| 17 | return false; |
| 18 | } |
| 19 | } |
| 20 | } |
| 21 | return true; |
| 22 | } |
| 23 | |
| 24 | private boolean isCyclic(List<List<Integer>> adj, int[] visited, int curr) { |
| 25 | if (visited[curr] == 2) { |