Leet Code 210. Course Schedule II - Kahn's Algorithm

https://leetcode.com/problems/course-schedule-ii/

Here we need to print the topological sort using Kahn's Algo

package pep.Day44;

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Queue;

public class LeetCode_210_Course_Schedule_II {
    public static void main(String[] args) {
        System.out.println(findOrder(2, new int[][]{{1, 0}}));
    }

    public static int[] findOrder(int n, int[][] pre) {
        ArrayList<Integer>[] graph = new ArrayList[n];

        for (int i = 0; i < n; i++) {
            graph[i] = new ArrayList<>();
        }

        int[] indegree = new int[n];

        for (int[] p : pre) {
            graph[p[0]].add(p[1]);
            indegree[p[1]]++;
        }

        Queue<Integer> que = new LinkedList<>();

        for (int i = 0; i < n; i++)
            if (indegree[i] == 0)
                que.add(i);

        int[] ansArr = new int[n];
        int idx = -1;
        while (!que.isEmpty()) {
            int out = que.remove();
            ansArr[n - 1 - (++idx)] = out;
            for (int nbr : graph[out]) {
                if (--indegree[nbr] == 0)
                    que.add(nbr);
            }
        }

        return idx < n - 1 ? new int[0] : ansArr;

    }
}