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43. Multiply Strings

https://leetcode.com/problems/multiply-strings

Python​

Use enumerate index as pos​

class Solution:
    def multiply(self, num1: str, num2: str) -> str:
        result = 0
        for pos1, char1 in enumerate(num1[::-1]):
            for pos2, char2 in enumerate(num2[::-1]):
                result += int(char1) * int(char2) * (10**(pos1+pos2))
        return str(result)

Self-calculate power​

(Second try, not that better solution)

class Solution:
    def multiply(self, num1: str, num2: str) -> str:
        ans = 0
        power = 0

        for ns1 in num1[::-1]:
            level_total = 0
            level_pwr = 0
            for ns2 in num2[::-1]:
                n1 = ord(ns1) - ord('0')
                n2 = ord(ns2) - ord('0')
                mult = n1 * n2

                level_total += mult * (10**level_pwr)
                level_pwr += 1

            ans += level_total*(10**power)
            power += 1

        return str(ans)