Interview classics

The questions interviewers actually ask, with the part they are really testing made explicit. Each one has an answer anyone finds in a minute and a better one that needs you to spot the repeated work, and the grader holds you to the better one.

8 exercisesdifficulty 2–3~170 min in total

—Exercises 8 exercises

Brackets that close in the right order a list as a stack, matching pairs ~20 min The best day to buy and the best day to sell running minimum, one pass ~20 min The first letter that appears only once count first, then look, Counter ~15 min The one ticket number nobody handed in the sum you expect, arithmetic instead of searching ~15 min Two numbers that add up to a target dict as a lookup, one pass ~20 min The best run of consecutive days Kadane’s algorithm, extend or start again ~25 min The longest stretch with no letter repeated sliding window, last seen position ~30 min Merge the meetings that overlap sort first, compare with the last kept ~25 min