void Graph::tarjan(int node, Stack &successors, Stack &recStack, Hashtable &visited, Hashtable &explored, int &index){
    int j, last, dummy = -1, indexOut, flag = 0;;
    index++;
    visited.addVisited(node, dummy);
    successors.push(node, index, index);
    recStack.push(node, index, index);
    while(recStack.getSize() > 0){
        //check top's low_rank and save it in min_lowrank
        last = -1;
        indexOut = nodeIndexOut_.getListHead(node);
        if(indexOut < 0)
            countOut = 0;
        else
            countOut = bufferOut_.getTotalNodeCount(indexOut);
        for(j = 0; j < countOut; j++){
            neighbor = bufferOut_.getNeighbor(indexOut, j, last, node);
            if(!visited.searchVisited(neighbor, dummy)){ //TODO: too slow, checks marked neighbors multiple times
                explored.addVisited(neighbor, dummy);
                node = neighbor;
                index++;
                visited.addVisited(node, dummy);
                successors.push(node, index, index);
                recStack.push(node, index, index);
                flag = 1;
                break;
            }
            else{
                explored.addVisited(neighbor, dummy);
                node.lowlink = min(node.lowlink, neighbor.lowlink);
            }
        }
        if(flag){ //if we ended up here from break, recurse
            flag = 0;
            continue;
        }
        if(node.lowlink < node.index){
            node1 = recStack.pop();
            node = recStack.top();
            node.lowlink = min(node.lowlink, node1.lowlink);
        }
        else{
            do{
                x = successors.pop();
                //fix x's SCC
            }(while x != node);
            recStack.pop();
        }
    }
}