MultiplyStrings.java

package LeetcodePractice;
public class MultiplyStrings {

        public static String multiply(String num1, String num2) {
            int m = num1.length();
            int n = num2.length();
    
            int[] result = 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 sum = mul + result[i + j + 1]; 
    
                    result[i + j + 1] = sum % 10;
                    result[i + j] += sum / 10; 
                }
            }

            StringBuilder sb = new StringBuilder();
            for (int num : result) {
                if (!(sb.length() == 0 && num == 0)) { 
                    sb.append(num);
                }
            }
    
            return sb.length() == 0 ? "0" : sb.toString(); 
        }
    
        public static void main(String[] args) {
            String num1 = "123";
            String num2 = "456";
    
            String result = multiply(num1, num2);
    
            System.out.println("Product: " + result);
        }
    }