Last updated on October 10th, 2024 at 02:11 am

Here, We see Multiply Strings LeetCode Solution. This Leetcode problem is done in many programming languages like C++, Java, JavaScript, Python, etc., with different approaches.

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Multiply Strings LeetCode Solution

Problem Statement

Given two non-negative integers num1 and num2 represented as strings, return the product of num1 and num2, also represented as a string.

Example 1:
Input: num1 = "2", num2 = "3"
Output: "6"

Example 2:
Input: num1 = "123", num2 = "456"
Output: "56088"

1. Multiply Strings Leetcode Solution C++

class Solution {
public:
    string multiply(string num1, string num2) {
        if(num1=="0"||num2=="0"){return "0";}
        int n = num1.length(),m = num2.length();
        string ans(n+m,'0');

        for(int i=n-1;i>=0;i--){
            for(int j=m-1;j>=0;j--){
                int num = (num1[i] - '0') * (num2[j] - '0') + ans[i+j+1] - '0';
                ans[i+j+1] = num%10 + '0';
                ans[i+j] += num/10;
            }
        }
        for(int i=0;i<ans.length();i++){
            if(ans[i] != '0'){ return ans.substr(i);}
        } 
        return "0";      
    }
};

2. Multiply Strings Leetcode Solution Java

class Solution {
    public String multiply(String num1, String num2) {
    int m = num1.length(), n = num2.length();
    int[] pos = new int[m + n];
   
    for(int i = m - 1; i >= 0; i--) {
        for(int j = n - 1; j >= 0; j--) {
            int mul = (num1.charAt(i) - '0') * (num2.charAt(j) - '0'); 
            int p1 = i + j, p2 = i + j + 1;
            int sum = mul + pos[p2];

            pos[p1] += sum / 10;
            pos[p2] = (sum) % 10;
        }
    }  
    
    StringBuilder sb = new StringBuilder();
    for(int p : pos) if(!(sb.length() == 0 && p == 0)) sb.append(p);
    return sb.length() == 0 ? "0" : sb.toString();      
    }
}

3. Multiply Strings Leetcode Solution Javascript

var multiply = function(num1, num2) {
      let b = BigInt(num1) * BigInt(num2)
      return String(b)
};

4. Multiply Strings Leetcode Solution Python

class Solution(object):
    def multiply(self, num1, num2):
        return str(self.strint(num1)*self.strint(num2))
    def strint(self,n):
        result=0
        for i in range(len(n)):
            result = result*10 + ord(n[i])-ord('0')
        return result