The short answer is you must practice very hard on HackerRank for speed. They typically give five questions, and the fifth one is supposed to be hard.

I found that my speed was about 30 minutes per question, meaning 1.5 hours is too short. By the time I finished the third question, time was already over. I had taken a HackerRank test for another company, and my average time was 30 minutes per question. I am still not sure how to improve this speed.

Incidentally, since I realized I wouldn't be able to finish, I skipped to the last question to see how difficult it was. I saw all five questions. Strangely, I would rank the last question as the second easiest. It was the fourth question that was the most difficult. I am ranking them based on the test scenarios they cover, which is correct according to my experiences.

I obviously didn't make it. But if you want to try, then attempt only three questions: the first two and then the fifth one. If you can do more, then that's better, but I am not sure how someone can be faster. My thinking time was negligible. It was typing and reading code back that took all the time.

Also, just for curiosity, I checked HackerRank's ranking of questions. I did find their ranking is not always correct. I randomly took one difficult question to test and found it to be the easiest one to date. It was easiest because only five lines were supposed to be modified. For me, time is always proportional to the typing volume.

Incidentally, I did try to shorten variable names to finish questions in time. Unfortunately, it was too late.

My advice:

• Give shorter variable and function names so you save time.
• Attempt the first two questions and then the last. If time is left, then attempt the remaining ones.

As per their guidance, they place the most weightage on the last question, so you should be through. Note that all the questions are solvable by anyone knowing a little. Speed is the main issue.