Leetcode Problem: 1281. Subtract the Product and Sum of Digits of an Integer

Description:

Given an integer number n, return the difference between the product of its digits and the sum of its digits.

Example 1:

Input: n = 234
Output: 15 
Explanation: 
Product of digits = 2 * 3 * 4 = 24 
Sum of digits = 2 + 3 + 4 = 9 
Result = 24 - 9 = 15

Example 2:

Input: n = 4421
Output: 21
Explanation: 
Product of digits = 4 * 4 * 2 * 1 = 32 
Sum of digits = 4 + 4 + 2 + 1 = 11 
Result = 32 - 11 = 21

Constraints:

• 1 <= n <= 10^5

Solution:

public class Solution {
    public int SubtractProductAndSum(int n) {
        int reminder;
        int sum = 0;
        int product = 1;
        while(n>0){
          sum = sum+(n%10);
          product = product*(n%10);
          n = n/10;
        }
        return product-sum;
    }
}

Approach:

Initialize variables:

• sum = 0 → to store sum of digits.
• product = 1 → to store product of digits.

Loop through all digits of n:

• The condition while (n > 0) keeps running until all digits are processed.

Extract last digit:

• (n % 10) gives the last digit of n.

Update sum and product:

• Add the digit to sum.
• Multiply the digit to product.

Remove last digit:

• n = n / 10 removes the last digit (integer division).

After loop ends:

• All digits have been processed.
• Compute the final answer: product - sum.