Get Expression Sums
Reported by candidates from Flexport's online assessment. Pattern, common pitfall, and the honest play if you blank under the timer.
Flexport's February OA included a problem called Get Expression Sums that doesn't have a published statement online yet. This is a gap in the problem bank. If your OA has this question, you're seeing a fresh or rotated prompt. The title hints at arithmetic evaluation or sum calculation from expressions. StealthCoder will read the problem on screen and give you the pattern in real time, so you won't be guessing on a live timer.
Pattern and pitfall
Without the verbatim problem text, the pattern could be arithmetic expression evaluation (parsing and computing sums), dynamic programming over subsets of an expression, or recursive sum computation over different groupings. The most common Flexport variant involves parsing an infix or postfix expression and computing all possible sums by choosing different operator precedences or groupings. The pitfall is off-by-one errors in tokenization, operator precedence bugs, or missing edge cases with negative numbers. If it's a DP problem, you'll need memoization on subexpression states. StealthCoder will parse the exact problem text on your screen and map it to the right approach the moment you see it.
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Get Expression Sums FAQ
What does 'Get Expression Sums' actually ask for?+
The problem likely asks you to compute all possible sums from an expression by choosing different ways to evaluate it, or to find the sum of all valid interpretations of a given string. Without the full text, assume it involves parsing and combinatorial evaluation. The OA will make it clear on screen.
Is this a parsing problem or a DP problem?+
Likely both. You'll parse the expression into tokens, then use recursion or DP to explore different evaluation orders or operator choices. Memoization on substring ranges is a common pattern for this type of question.
How do I prepare in 24 hours if I don't have the problem text?+
Study expression evaluation (postfix/infix conversion), recursive descent parsing, and DP on intervals. Know how to tokenize strings and handle operator precedence. These are the building blocks for any expression-sum variant.
What's the gotcha with this problem?+
Negative numbers, zero, and operator precedence. Also, make sure you're exploring all possible groupings if the problem allows parentheses. Off-by-one errors in parsing are common. Test edge cases early.
Is this problem still asked at Flexport?+
It was reported in February 2024. Flexport rotates problems frequently, so it may or may not appear in your OA. But the pattern is classic enough that similar variants are likely in their pool.