Evaluate an arithmetic expression
Company: Docker
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Technical Screen
Given a valid string expression containing non-negative integers, spaces, and the operators `+`, `-`, `*`, and `/`, return the computed result.
Requirements:
- The expression does not contain parentheses.
- Integer division truncates toward zero.
- The input may contain multi-digit numbers and arbitrary spaces.
- You must handle operator precedence correctly: multiplication and division before addition and subtraction.
Examples:
- `"3+2*2"` -> `7`
- `" 3/2 "` -> `1`
- `" 3+5 / 2 "` -> `5`
Discuss the time and space complexity of your approach.
Quick Answer: This question evaluates parsing and expression-evaluation skills, specifically handling operator precedence, integer division truncation, multi-digit numbers, and whitespace handling within the Coding & Algorithms domain.
Evaluate a valid expression with +, -, *, / and spaces, using precedence and truncating division toward zero.
Constraints
- Expression has no parentheses and is valid
Examples
Input: ('3+2*2',)
Expected Output: 7
Explanation: Multiplication before addition.
Input: (' 3/2 ',)
Expected Output: 1
Explanation: Truncates toward zero.
Input: (' 3+5 / 2 ',)
Expected Output: 5
Explanation: Prompt example.
Input: ('14-3/2',)
Expected Output: 13
Explanation: Division before subtraction.
Hints
- Collapse multiplication/division onto the previous stack term; sum additive terms at the end.