I applied to Amazon, and studied Algo for 6 months. I practiced all of the algo questions in GlassDoor, and all of the algo books I could find. I wasn't able to make it though :( As other people mentioned, you have very few chances because those companies value that kind of interview questions more than quality engineering. But please, give it a try, practice LEET code 24/7, and you might be able to make it! NEVER GIVE UP! Those 6 months of preparation for Amazon helped me land better jobs at better companies in the future. So that time is well spent.