Alternating Digit Sum
The task is to sum all the digits of a given integer n
, but with alternating signs starting with a positive sign for the most significant digit.
Here’s a simple way to accomplish this:
 Convert the integer to a string to easily access its individual digits.
 Iterate through the string, converting each digit back to an integer.
 Alternate the sign of each digit by using a sign variable that flips between 1 and 1.
 Sum the digits, taking the sign into account.
Implementation


Explanation
 For Input:
n = 521
 Iteration through digits:
(+5) + (2) + (+1)
 Output:
4
This code ensures that each digit is processed with the correct sign. Since we iterate through each digit exactly once, the complexity of this solution is ( O(m) ), where ( m ) is the number of digits in n
.