Step 1 / 6BFS starts. Enqueue source node 1. Front and rear both point to cell 0.
Step 2 / 6Discover neighbors of node 1. Enqueue nodes 2 and 4.
Step 3 / 6Dequeue node 1 (done). Process node 2 next. Front pointer advances.
Step 4 / 6Dequeue node 2 (done). Process node 4. Enqueue its neighbors 5 and 3.
Step 5 / 6Dequeue node 4 (done). Process node 5 next. Front advances to cell 3.
Step 6 / 6BFS complete. All reachable nodes have been visited.