Design Data Structures

Uber's coding rounds have a design-a-data-structure flavor that the loop leans on hard, and it usually shows up as a "machine-coding" exercise. The interviewer hands you a small interface, a class with two or three methods, and asks you to make every method hit a complexity target while the surrounding code stays clean enough to extend. The grade is not just "does it return the right answer." It is whether your structures hit the bound you committed to. They also check that the class is organized so the follow-up is a small change, and that your code survives the edge cases without crashing or returning the wrong thing.

These problems feel different from the array and graph questions because there is no clever traversal to find. The work is in the design itself. You are choosing a combination of building blocks, usually a hash map plus one more structure, so that each operation the interface promises lands in the time bound you committed to. Once you see which two structures fit together, the code is short. Getting there, and packaging it as a tidy class, is the part Uber is reading.