How should I practice Basic Calculator?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Amazon onsite interview problems in FastPrep.

Is Basic Calculator associated with Amazon?

FastPrep tags this as a Amazon onsite interview coding practice problem when the problem catalog has that company and stage context.

Problem · String

Basic Calculator

Learn this problem

● Hard

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Problem statement

Given a valid arithmetic expression s, return its evaluated integer value.

The expression may contain:

Non-negative integer literals.
The binary operators + and -.
Parentheses ( and ).
Spaces.
Unary + or - where a signed expression is valid.

Integer division is not needed because the expression contains no multiplication or division operators.

Function

calculate(s: String) → int

Examples

Example 1

s = "1 + 1"return = 2

The two operands sum to 2.

Example 2

s = " 2-1 + 2 "return = 3

Evaluate from left to right: 2 - 1 + 2 = 3.

Example 3

s = "(1+(4+5+2)-3)+(6+8)"return = 23

The first parenthesized group evaluates to 9, and 6 + 8 = 14, for a total of 23.

Constraints

1 <= s.length <= 3 * 10^5
s is a valid expression containing digits, +, -, (, ), and spaces.
Every intermediate and final result fits in a signed 32-bit integer.