The issue encountered is likely due to the marque and stop variables. In MATLAB, variables are passed by value and not by reference. This means that any modification to the variables within the recursive calls of dfs does not affect its value in the calling function unless explicitly returned.
You can modify the function as follows to return the correct output:
function [stop] = dfs(node, matrice_adjacence, marque, stop)
marque = [marque, node];
fils = find(matrice_adjacence(node, :));
for i = fils
if stop == 1
return;
end
if ~ismember(i, marque)
% Recursive call with the updated path
stop = dfs(i, matrice_adjacence, marque, stop);
else
stop = 1;
return;
end
end
end
The main differences between the original code and the modified code are:
- The fils array could include zeros, which might cause issues during iteration. Modified code only considers outgoing edges from the current node (node), which simplifies the logic and avoids unnecessary checks.
- The path is updated before entering the loop, ensuring that each recursive call correctly tracks the path.
- We directly check the membership and update stop correctly and return immediately when a cycle is detected, which ensures that the cycle detection is propagated back through the recursive calls.
Hope this helps!
