isCyclicUtil.cpp

public boolean isCycleUtil(int vertex, boolean[] visited, boolean[] recursiveArr) {
    visited[vertex] = true;
    recursiveArr[vertex] = true;

    //recursive call to all the adjacent vertices
    for (int i = 0; i < adjList[vertex].size(); i++) {
        //if not already visited
        int adjVertex = adjList[vertex].get(i);
        if (!visited[adjVertex] && isCycleUtil(adjVertex, visited, recursiveArr)) {
            return true;
        } else if (recursiveArr[adjVertex])
            return true;
    }
    //if reached here means cycle has not found in DFS from this vertex
    //reset
    recursiveArr[vertex] = false;
    return false;
}