dsa · medium

Multiply Strings

num1 and num2 are non-negative integers given as decimal strings (digits 0-9, no extra leading zeros except the number "0" itself). Return their product as a decimal string.

Arguments

• num1 — first non-negative integer as a decimal digit string
• num2 — second non-negative integer as a decimal digit string

Do not turn the whole strings into machine integers in one shot — the values may be longer than a 64-bit word. Multiply digit by digit.

Example

num1 = "2", num2 = "3" → "6".

num1 = "123", num2 = "456": 123×400 = 49200, 123×50 = 6150, 123×6 = 738, and 49200+6150+738 = 56088.

num1 = "0", num2 = "123" → "0".

Constraints

1 <= num1.length, num2.length <= 200 num1 and num2 consist of digits 0-9 Neither string has a leading zero unless it is exactly 0 Hidden tests include near-max size for this bound; a slower-than-intended solution TLEs.

Examples

Example 1

Input:
"2"
"3"

Expected:
6

Example 2

Input:
"123"
"456"

Expected:
56088

Example 3

Input:
"0"
"123"

Expected:
0

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