Cut Vertex or Articulation Point

    public class Main {
        
        static int[] low,dfsnum;
        static int num=1;
        static int noOfVertices;
        static boolean[] art;
        
        public static void main(String[] args) {
            
            noOfVertices=7;
            
            int[][] adjMatrix=new int[][]{
                {0,1,0,1,0,0,0},
                {1,0,1,0,0,0,0},
                {0,1,0,1,0,0,1},
                {1,0,1,0,1,1,0},
                {0,0,0,1,0,1,0},
                {0,0,0,1,1,0,0},
                {0,0,1,0,0,0,0}
            };
            low=new int[noOfVertices];
            dfsnum=new int[noOfVertices];
            art=new boolean[noOfVertices];
            
            cutVertices(adjMatrix,0,-1);
            
            System.out.println("Cut vertex / articulation points are: ");
            for(int i=0;i<noOfVertices;i++){
                if(art[i]){
                    System.out.println((char)('A'+i));
                }
            }
        }
        
        static void cutVertices(int[][] adjMatrix, int vertex,int p){
            low[vertex]=dfsnum[vertex]=num++;
            
            int child=0;
            for(int v=0;v<noOfVertices;v++){
                if(adjMatrix[vertex][v]==1) {
                    if(dfsnum[v]!=0){
                        low[vertex]=Math.min(low[vertex],dfsnum[v]);
                    }
                    else{
                        child++;
                        cutVertices(adjMatrix,v,vertex);
                        low[vertex] = Math.min(low[vertex],low[v]);
                        if(low[v]>=dfsnum[vertex]){
                            art[vertex]=true;
                        }
                    }
                }
            }
            
            if(p==-1 && child<2){
                art[vertex]=false;
            }
        }
}