How should I practice Add Signed Character Arrays?

Start by reading the full statement, solve the visible examples, then compare the pattern against related ByteDance phone screen problems in FastPrep.

Is Add Signed Character Arrays associated with ByteDance?

FastPrep tags this as a ByteDance phone screen coding practice problem when the problem catalog has that company and stage context.

Problem · Array

Add Signed Character Arrays

Learn this problem

● Medium

ByteDanceFULLTIMEPHONE SCREEN

Problem statement

Two signed decimal integers are stored in character arrays left and right. Each array contains an optional leading + or -, followed by one or more decimal digits.

Return their exact sum as a normalized character array:

Do not use a fixed-width numeric conversion or arbitrary-precision integer library.
Remove leading zeros from the magnitude.
Use a leading - only when the result is negative.
Represent zero exactly as ['0'].

Function

addSignedNumbers(left: char[], right: char[]) → char[]

Examples

Example 1

left = ["-","1","2","3"]right = ["4","5"]return = ["-","7","8"]

The operands are -123 and 45, whose sum is -78.

Example 2

left = ["9","9","9"]right = ["1"]return = ["1","0","0","0"]

A carry propagates through all three digits, producing 1000.

Example 3

left = ["-","5","0"]right = ["+","5","0"]return = ["0"]

Equal magnitudes with opposite signs cancel, and zero has no sign.

Constraints

1 <= left.length, right.length <= 200000
Each input has an optional leading sign followed by at least one decimal digit.
Each input is a valid integer encoding; leading zeros are allowed.
The total input size fits in memory.