Algorithm 1. Proposed discrete stepping ahead firefly algorithm.

Step 1: Initialize population of fireflies

Random population of N solutions using LD constraint sorting

Each exam is placed in non-conflicting slot

Initialize all variables

while t < MaxGeneration do

for i = 1: n (all n fireflies) do

for j = 1: n (all n fireflies) do

Step 2: Evaluation

if $I_j\le I_i$ then

move firefly in relation to i using the Kempe move; $I_{new}$

while count $\le$ 5 & Ii = Inew do

move firefly in relation to i using the Kempe move; $I_{new}$

end

end

Step 3: Stepping ahead

if Stepping ahead is activated then

move firefly in relation to j using the Kempe move; $I_{new}$

while count $\le$ 5 & $I_{new}-I_j>Q\parallel I_i=I_{new}$ do

move firefly in relation to $I_{new}$ using the Kempe move 1 & 2; $I_{new}$

end

end

end

nothing

end

Rank fireflies and update best using threshold and probability; Preference utilized;

if No improvement then

Stepping ahead is activated;

else

Stepping ahead is deactivated;

end

if No improvement due to stepping ahead then

restart 10 steps back where there was improvement;

end

end

Post processing the results and visualization;