Multiply Strings

Medium · Math & Geometry

You are given two non-negative integers, each represented as a string of digits with no leading zeros (unless the value is exactly zero). Compute their product and return it as a string, again with no leading zeros. Treat this as a digit-by-digit arithmetic exercise rather than converting the whole strings straight into a built-in big integer type. The inputs can be very long, longer than what fits in a normal fixed-size integer in many languages.

Examples

Input:  num1 = "2", num2 = "3"
Output: "6"
Why:    2 times 3 equals 6.

Input:  num1 = "123", num2 = "456"
Output: "56088"
Why:    123 times 456 equals 56088.

Input:  num1 = "0", num2 = "52"
Output: "0"
Why:    Anything multiplied by zero is zero.

Constraints

1 <= num1.length, num2.length <= 200, both strings contain only digits 0-9 and have no leading zeros unless the number itself is "0"

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Practise Multiply Strings

This statement is written for CodeSpeek. The problem is part of the NeetCode 150 list; Watch NeetCode's explanation of Multiply Strings. Reference solutions from the NeetCode repository (MIT) are used to verify our tests.