alternating_digit_sum.cpp

//question//



You are given a positive integer n. Each digit of n has a sign according to the following rules:

The most significant digit is assigned a positive sign.
Each other digit has an opposite sign to its adjacent digits.
Return the sum of all digits with their corresponding sign.

 

Example 1:

Input: n = 521
Output: 4
Explanation: (+5) + (-2) + (+1) = 4.
Example 2:

Input: n = 111
Output: 1
Explanation: (+1) + (-1) + (+1) = 1.
Example 3:

Input: n = 886996
Output: 0
Explanation: (+8) + (-8) + (+6) + (-9) + (+9) + (-6) = 0.
 

Constraints:

1 <= n <= 109



//solution//


class Solution {
public:
    int alternateDigitSum(int n) {
        int sum = 0;
        string s = to_string(n);
        for(int i=0;i<s.size();i++){
            if(i%2==0){
                sum += s[i]-'0';
            }
            else{
                sum -= s[i]-'0';
            }
        }
        return sum;
    }
};