Basic BFS

Solution.java

class Solution {
    // Function to return Breadth First Traversal of given graph.
    public ArrayList < Integer > bfsOfGraph(int V, ArrayList < ArrayList < Integer >> adj) {
        ArrayList < Integer > ans = new ArrayList < Integer > ();
        int[] color = new int[V];
        color[0] = 1;
        Queue < Integer > q = new LinkedList < > ();
        q.add(0);
        ans.add(0);
        while (q.size() != 0) {
            int u = q.remove();
            for (int v: adj.get(u)) {
                if (color[v] == 0) {
                    q.add(v);
                    ans.add(v);
                    color[v] = 1;
                }
            }
        }
        return ans;
    }
}