Adding Long Numbers in Strings

Easy

You are given two strings left and right, each the decimal form of a non-negative integer. The numbers can be very long. Return their sum as a string. You may not convert a whole string into a number or rely on built-in big-number arithmetic — add them digit by digit. The inputs have no leading zeros (except for the string "0" itself), and the answer must not have any either.

Example 1

left='2049', right='77' → '2126'

2049 + 77 = 2126.

Example 2

left='999', right='1' → '1000'

The carry runs through all three digits and the answer grows by one digit: 1000.

Example 3

left='0', right='58' → '58'

0 + 58 = 58.

Constraints

1 ≤ left.length, right.length ≤ 10⁴
Both strings contain digits only
No leading zeros, except for the string "0" itself

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Topics

Math String Simulation

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Input

left='2049', right='77'

Expected

'2126'

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