Key-Value Stores & Caches

SoFi likes build-a-store problems in phone screens and Staff onsites. Each one starts as a plain hash map and then needs something a map can't do alone, and two of the problems below share the same answer to that.

The third is a longer build. It runs about 90 minutes and grows in levels as you go. Both the structure of your code and the tests at each level count, so finish each level cleanly before you start the next one.

Your code gets read closely in all of these. Keep the list work in small helpers so the public methods stay a few lines long. A scaling question can follow the code, and one screen moved on to spreading the store across machines.

SoFiPremium lesson · Coding round

The 3 SoFi problems are below.

1. 1A Premium questionCoding · Medium
2. 2A Premium questionCoding · Medium
3. 3A Premium questionCoding · Hard

Each with hints, the follow-up and a tested solution.

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