LeetCode-in-Java
2544. Alternating Digit Sum
Easy
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
public class Solution {
public int alternateDigitSum(int n) {
String s = Integer.toString(n);
char[] arr = s.toCharArray();
int res = 0;
for (int i = 0; i < arr.length; i++) {
res += (int) Math.pow(-1, i) * (arr[i] - '0');
}
return res;
}
}