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Multiply Strings

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Description

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

Solution

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class Solution:
    def multiply(self, num1, num2):
        """
        :type num1: str
        :type num2: str
        :rtype: str
        """
        lens1 = len(num1)
        lens2 = len(num2)
        if lens1 == 0 or lens2 == 0 or int(num1) == 0 or int(num2) == 0:
            return "0"
        
        ret = ""
        multi_matrix = []
        max_len = -1
        for i in range(0, lens2):
            string = self.multiply_one_digit(num1, num2[-1-i]) + "0" * i
            max_len = max(max_len, len(string))
            multi_matrix.append(string)
            
        has_value = True
        append = 0
        for digit in range(0, max_len):
            has_value = False
            value = 0
            for index in range(len(multi_matrix)):
                if digit < len(multi_matrix[index]):
                    value += int(multi_matrix[index][-1-digit])
            value += append
            append = value // 10
            ret = str(value % 10) + ret
            
        if append != 0:
            ret = str(append) + ret
        return ret
            
            
        
    def multiply_one_digit(self, num, digit):
        ret = ""
        append = 0
        for i in range(0, len(num)):
            result_digit = str((int(num[-1-i])*int(digit) + append) % 10)
            ret = result_digit + ret
            append = (int(num[-1-i])*int(digit) + append) // 10
            
        print (ret)
        print (append)
        if append != 0:
            ret = str(append) + ret
         
        return ret