Math and Search Puzzles

The statements here fit in a few lines, and so does the code that solves them. Your time goes into spotting one fact, such as a sequence that grows so fast you can list every term, or a single number that captures the whole state.

One of the four is different. It has no shortcut like that, so you search, and the order you search in decides whether it finishes in time. Pick an order where a wrong choice fails within a step or two, and the search stays small.

Math problems still lose points to overflow and runtime errors, often on hidden tests far bigger than the samples. Choose your integer widths before you write the loop, especially when values can reach 10^18.

One of these has opened an intern assessment as question 1 of 4, ahead of three harder problems. Each walkthrough below starts with the fact that shrinks its problem, or with the order that prunes the search.

Hudson River TradingPremium lesson · Coding round

The 4 Hudson River Trading problems are below.

1. 1A Premium questionCoding · Easy · Frequently asked
2. 2A Premium questionCoding · Medium
3. 3A Premium questionCoding · Hard

+ 1 more in this lesson

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

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