If you can't spend 1-2 days revisiting old basic algorithms like this, you are not even self-motivated or capable of learning on the job to probably join the "bigger names" like you mention. Interviews like these test how well you are at basic comp. sci problems. I used to be like you and from a much more distant country but eventually I realized these questions have a lot of merit: if you don’t know these basics all you are capable of is gluing some APIs and solving some of integration/compatibility problems in different platforms. Not a good fit for companies who are creating those APIs, platforms and breaking new ground. Also, think about it from a statistics point of view: you are more likely to get false positive with people who can’t pass that simple question those who can.