applyRule1.m

function [A, nodes] = applyRule1(A, nodes)
N = size(A,1);

% Find all unused node (circle node)
circleNodeIndexes = [];
for i = 1:N
    if isequal(nodes{i}.shape, 'o')
        circleNodeIndexes = [circleNodeIndexes; i];
    end
end

% Chose random node
if length(circleNodeIndexes) <=0
    return; % Exit if no circle nodes are found
end
newNodeIndex = circleNodeIndexes(randi(length(circleNodeIndexes)));

% Find all edge of A in form of (nodea, nodeb)
edges = []; % Initialize empty list

for i = 1:N
    for j = i+1:N  % check only upper triangle
        if A(i,j) ~= 0
            edges = [edges; i, j];
        end
    end
end

% Chose a random edge
idx = randi(size(edges,1));
e = edges(idx, :);
a = e(1);
b = e(2);

A(newNodeIndex, a) = 1;
A(newNodeIndex, b) = 1;

A(a, newNodeIndex) = 1;
A(b, newNodeIndex) = 1;

nodes{newNodeIndex}.shape = 's'; % Update the shape of the new node


end