Practice/Oracle/Add two decimal strings e.g. '123.45' + '236.7'

Add two decimal strings e.g. '123.45' + '236.7'

CodingOptional

Problem

You are given two non-negative numbers represented as strings. Each string may contain a decimal point followed by fractional digits. Your task is to add these two numbers and return the sum as a string.

The decimal points in the two input strings may appear at different positions, meaning the numbers can have different numbers of fractional digits. You must implement this addition without converting the strings to floating-point numbers (to avoid precision issues).

Requirements

1. Implement string-based addition to avoid floating-point precision errors
2. Handle cases where one or both numbers have no decimal point
3. Handle cases where the numbers have different numbers of digits after the decimal point
4. Remove trailing zeros from the fractional part of the result
5. If the result has no fractional part (or it's all zeros), omit the decimal point entirely

Constraints

• 1 <= num1.length, num2.length <= 10^4
• num1 and num2 consist of digits and at most one decimal point
• num1 and num2 represent valid non-negative decimal numbers
• No leading zeros except for numbers less than 1 (e.g., "0.5" is valid)
• You cannot use built-in big decimal libraries or convert to float/double

Examples

Example 1:

` Input: num1 = "123.45", num2 = "236.7" Output: "360.15" Explanation: We align the decimal points mentally: 123.45

• 236.70

360.15 `

Example 2:

Input: num1 = "999", num2 = "1" Output: "1000" Explanation: Both are integers, simple addition with carry propagation.

Example 3:

Input: num1 = "0.001", num2 = "0.999" Output: "1.0" Explanation: The sum is 1.000, but we keep one decimal place to show it was a decimal operation. Actually, trailing zeros should be removed, so "1.0" or "1" depending on implementation choice. For consistency, "1.0" is acceptable, but "1" is cleaner.