How to track the lists generated in each for loop?

Gv = graph({'s1' 's_1' 's2' 's_2' },{'s2' 's_2','s3' 's_3'});
Gv.Nodes.Memory = [8,8,7,7,8,7]';
Gv.Nodes.Service = {'s1','s2','s_1','s_2','s3','s_3'}';
Application = Gv.Nodes;

Gp = graph({'n1' 'n1' 'n2' 'n2' 'n3' 'n4'},{'n2' 'n4' 'n3' 'n4' 'n5' 'n5'});
Gp.Nodes.Memory = [15,15,15,15,15]';

Gvsub = graph();

for i = 1:numnodes(Gv)
    for j = 1:numnodes(Gp)
         List = find(Gv.Nodes.Memory(i) <= Gp.Nodes.Memory); % WE MUST ALSO ADD AVAILABILITY      
    end
    disp(List);
    first_element = List(1);
    disp(Gv.Nodes.Service(i)); %SELECTED SERVICE FOR ALLOCATION
    if isempty(Gvsub.Nodes)
     Gp.Nodes.Memory(first_element) = Gp.Nodes.Memory(first_element) - Gv.Nodes.Memory(i);
     Gp.Nodes
    else
     Gp.Nodes.Memory(first_element) = Gp.Nodes.Memory(first_element) - Gv.Nodes.Memory(i);
     Gp.Nodes
    end
  Application(1,:) = [];   % REMOVING THE USED ROW AFTER BEING USED
end

In the OUTPUT we can see that s1 and s_1 generates the same list 1,2,3,4,5 and both of them gets allocated in 1.

How to check say during allocation of s_1 that 1 was already used by any other service( in this case s1 was already allocated in 1) or not?