private static DLL<Integer> vojska(DLL<Integer> list, int a, int b, int c, int d) {

        DLLNode<Integer> current = list.getFirst();
        DLLNode<Integer> startA = null, endB = null, startC = null, endD = null;

        while(current != null){

            if(current.element.equals(a)) {
                startA = current;
            } else if (current.element.equals(b)) {
                endB = current;
            } else if (current.element.equals(c)) {
                startC = current;
            } else if (current.element.equals(d)) {
                endD = current;
            }

            current = current.succ;
        }

        DLLNode<Integer> startA_pred = startA.pred;
        DLLNode<Integer> startC_pred = startC.pred;
        DLLNode<Integer> endB_succ = endB.succ;
        DLLNode<Integer> endD_succ = endD.succ;

        current = list.getFirst();

        while(current != null) {

            if(current.equals(startA)) {

                if(startA.pred != null)
                    startA_pred.succ = startC;

                startC.pred = null;
                startC.pred = startA_pred;

                endD.succ = endB_succ;
                endB_succ.pred = endD;
            }

            if(current.equals(startC)) {

               if(endD.succ != null)
                   endD_succ.pred = endB;

                startC_pred.succ = startA;
                startA.pred = startC_pred;

                endB.succ = null;
            }

            current = current.succ;
        }

        return list;
    }