Multiply Two String

Multiply Two Strings

Problem Statement

Given two numbers as strings s1 and s2. Calculate their Product.
Note : The numbers can be negative.

Example 1

Input :
s1 = "33"
s2 = "2"

Output : 66

Example 2

Input :
s1 = "11"
s2 = "23"

Output : 253

Task

You don't need to read input or print anything. Your task is to complete the function multiplyStrings() which takes two strings s1 and s2 as input and returns their product as a string.

Expected Time Complexity : O(n1 * n2).
Expected Auxiliary Space : O(n1 + n2); where n1 and n2 are sizes of strings s1 and s2 respectively.

Constraints :
1 <= Length of s1 and s2 <= 10³

Solutions

Java Solution

class Solution
{
    public String multiplyStrings(String s1,String s2)
    {
        //code here.
        BigInteger n1 = new BigInteger(s1);
        BigInteger n2 = n1.multiply(new BigInteger(s2));
    
        return String.valueOf(n2);
    }
}