To be honest I was a bit taken aback by the author not being able to implement a BFS. It&#x27;s a fairly standard and really simple algorithm and it&#x27;s probably one of the most common ones to actually implement because of a need in your day-to-day work.<p>What do you do if you have a nested data structure (like a tree) and want to print it in order? You write a simple BFS on it.<p>It&#x27;s not even a question where you <i>need</i> prior knowledge on the algorithm, it&#x27;s just logical. He could&#x27;ve easily asked &quot;Print the contents of this tree to screen&quot; and it would&#x27;ve been the same.<p>I can see how some questions like implementing quick or merge sort can be annoying, most libraries have a sort() function that usually implement either (or similar), you don&#x27;t often have to write them yourself, but a BFS does not fall into that category in my opinion.