Evaluate dependent variable expressions
Company: Instacart
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: Medium
Interview Round: Onsite
##### Question
Given a target variable name and a list of assignment strings of the form 'Ti = expression' where the expression is either a number, a single variable, or arithmetic (+, −) over variables/numbers, compute the numeric value of the target variable. Extend to handle expressions that reference other variables recursively; detect cycles or unsolvable references and report an error.
Quick Answer: This question evaluates a candidate's ability to parse and evaluate assignment expressions, resolve inter-variable dependencies, and detect cycles or unsolvable references.