Tarjan's Algorithm

public class Main {

    static boolean[] visited;
    static int[][] adjMatrix;
    static int noOfVertices;
    static int[] dfsnum,low;
    static int num=0;
    
    public static void main(String[] args) {

        noOfVertices=4;
        adjMatrix=new int[][]{
            {0,1,0,1},
            {0,0,1,0},
            {1,0,0,1},
            {0,0,0,0}
        };
        System.out.println("Each line is a list of vertex which form \na strongly connected component:");
        stronglyConnected();
    }
    
    static void stronglyConnected(){
        visited=new boolean[noOfVertices];
        Stack<Integer> stack=new Stack<>();
        dfsnum = new int[noOfVertices];  
        low = new int[noOfVertices];  
        
        for(int i = 0;i < noOfVertices; i++) { 
            dfsnum[i] = -1; 
            low[i] = -1; 
        }
        
        for(int vertex = 0;vertex < noOfVertices; vertex++) { 
            if(dfsnum[vertex] == -1){
                findSC(vertex,stack);
            }
        }
    }
    
    static void findSC(int vertex, Stack<Integer> stack){
        dfsnum[vertex] = low[vertex] = num++;
        stack.push(vertex);
        visited[vertex] = true;
        
        for(int v = 0; v < noOfVertices; v++) { 
            if(adjMatrix[vertex][v]==1){
                if(dfsnum[v] == -1){
                    findSC(v,stack);
                    low[vertex]=Math.min(low[v],low[vertex]);
                }
                else if(visited[v]){
                    low[vertex]=Math.min(dfsnum[v],low[vertex]);
                }
            }
        }
        
        int w = -1;  
        if (low[vertex] == dfsnum[vertex]) 
        { 
            while (w != vertex) 
            {  
                w = (int)stack.pop(); 
                System.out.print(w + " "); 
                visited[w] = false; 
            } 
            System.out.println();  
        } 
    }
}