USA | Verily Life Sciences Technical Phone

Completed technical phone screen with Verily Life Sciences. Got asked this problem

Question

Given an arithmetic expression like a-(b+c) return a simplified expression.

Examples:

• a-(b+c) gives a-b-c
• a+(a+b) gives a+a+b

Requirements:

• Variables are single letter. Don't worry about subscripts. Keep it simple
• Operations are only addition and subtraction. No worries about multiplication and division
• Followup: in math, you combine like terms when simplifying an expression. Modify your implementation to support that

Reflection

• Talked out my thought process and interviewer was very collaborative
• I think I got a much better handle on the recursion after solving "decoding an encoding" in a different interview
• Had a bit of trouble handling the open parentheses case and "combining the results" while accounting for negation. Interviewer gave me hint here and I was able to run with it
• Started with simple cases and then stress tested with other edge case. Interviewer liked my progress so far