Leet Code 207. Course Schedule I - Kahn's Algorithm

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

Same as Kahn's Algorithm, here we need to return True -> if all nodes are traversed i.e. all dependencies will be resolved, else False

package pep.Day44;

import java.util.*;

public class LeetCode_207_Course_Schedule {
    public static void main(String[] args) {
        System.out.println(canFinish(2, new int[][]{{1, 0}}));
    }

    public static boolean canFinish(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 < indegree.length; i++) {
            if (indegree[i] == 0)
                que.add(i);
        }

        ArrayList<Integer> ans = new ArrayList<Integer>();

        while (!que.isEmpty()) {
            int rem = que.remove();

            ans.add(rem);

            for (int nbr : graph[rem]) {
                if (--indegree[nbr] == 0) {
                    que.add(nbr);
                }
            }

        }

        return n == ans.size();
    }
}