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Leetcode
Medium
Math
Strings
Alternating Digit Sum
Compute the alternating sum of a number’s digits, starting from the most significant digit with a positive sign.
Acceptance 0%
Problem Statement
Given a decimal number, evaluate the sum of its digits with alternating signs from left to right. The first digit is added, the second is subtracted, the third is added again, and so on until all digits are processed.
Return the final total.
Input Format
- One non-negative integer.
Output Format
- One integer equal to the alternating digit sum.
Constraints
- Use one pass over the digits.
- The number is non-negative.
Examples
Sample cases returned by the problem API.
Example 1
Input
n = 521
Output
4
Explanation
5 - 2 + 1 = 4.
Example 2
Input
n = 1111
Output
0
Explanation
1 - 1 + 1 - 1 = 0.
Show 1 more example
Example 3
Input
n = 886996
Output
0
Explanation
8 - 8 + 6 - 9 + 9 - 6 = 0.
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