Implement three whiteboard coding tasks
Coding Challenges
This interview consists of three distinct coding challenges designed to assess your algorithmic thinking, data structure knowledge, and implementation skills.
1. Binary Search
Given a sorted array of integers and a target value, implement a function that returns the index of the target if it exists within the array. If the target is not found, return -1. The expected time complexity for this operation is O(log n).
2. Randomized Set Data Structure
Design and implement a data structure that supports the following operations in average O(1) time:
insert(x): Adds elementxto the set if it is not already present.remove(x): Deletes elementxfrom the set if it is present.getRandom(): Returns a uniformly random element from the current set of elements.
3. Expression Evaluator
Implement a function that evaluates a given string expression. The string will contain non-negative integers, spaces, and the arithmetic operators +, -, *, and /. The evaluation must respect standard operator precedence (multiplication and division before addition and subtraction).
As a follow-up, extend your evaluator to correctly handle expressions that include nested parentheses.
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Core dilemma
For these coding problems, the central engineering conflict is balancing algorithmic efficiency and data structure selection to meet strict performance constraints (e.g., O(log n), O(1) average time) while ensuring correctness, robustness against all edge cases, and producing clean, maintainable code. It's a trade-off between theoretical optimal performance and practical, bug-free implementation.
3 tradeoffs and 3 stress tests locked
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Unlock the interviewer X-Ray rubric, tradeoff matrix, stress tests, clarifying questions, and key concepts.
Implement three whiteboard coding tasks
Coding Challenges
This interview consists of three distinct coding challenges designed to assess your algorithmic thinking, data structure knowledge, and implementation skills.
1. Binary Search
Given a sorted array of integers and a target value, implement a function that returns the index of the target if it exists within the array. If the target is not found, return -1. The expected time complexity for this operation is O(log n).
2. Randomized Set Data Structure
Design and implement a data structure that supports the following operations in average O(1) time:
insert(x): Adds elementxto the set if it is not already present.remove(x): Deletes elementxfrom the set if it is present.getRandom(): Returns a uniformly random element from the current set of elements.
3. Expression Evaluator
Implement a function that evaluates a given string expression. The string will contain non-negative integers, spaces, and the arithmetic operators +, -, *, and /. The evaluation must respect standard operator precedence (multiplication and division before addition and subtraction).
As a follow-up, extend your evaluator to correctly handle expressions that include nested parentheses.