// Your runtime beats 29.57 % of java submissions.
class Solution {
    public int[] findOrder(int numCourses, int[][] prerequisites) {
        ArrayList<Integer> nodes = new ArrayList<>();
        int[] dc = new int[numCourses];
        ArrayList<ArrayList<Integer>> deps = new ArrayList<ArrayList<Integer>>();

        for (int i = 0; i < numCourses; i++) {
            nodes.add(i);
            deps.add(new ArrayList<Integer>());
        }

        for (int[] req: prerequisites) {
            deps.get(req[1]).add(req[0]);
            dc[req[0]] += 1;
        }

        List<Integer> res = new ArrayList<>();

        while (nodes.size() > 0){
            int out = -1;

            for (int node: nodes) {
                if (dc[node] == 0) {
                    out = node;
                    break;
                }
            }

            if (out == -1) return new int[0];

            nodes.remove(new Integer(out));
            for (int node: deps.get(out)) dc[node] -= 1;

            res.add(out);
        }

        int[] result = new int[numCourses];
        for (int i = 0; i < numCourses; i++) result[i] = res.get(i);
        return result;
    }
}