2180. Count Integers With Even Digit Sum

QUESTION:

Given a positive integer num, return the number of positive integers less than or equal to num whose digit sums are even.

The digit sum of a positive integer is the sum of all its digits.

Example 1:

Input: num = 4
Output: 2
Explanation:
The only integers less than or equal to 4 whose digit sums are even are 2 and 4.

Example 2:

Input: num = 30
Output: 14
Explanation:
The 14 integers less than or equal to 30 whose digit sums are even are
2, 4, 6, 8, 11, 13, 15, 17, 19, 20, 22, 24, 26, and 28.

Constraints:

1 <= num <= 1000

EXPLANATION:

for循环去挨个获取, 将每个数字进行string, 用tmp进行相加. 然后将tmp来判断是否是偶数. 返回结果.

SOLUTION:

class Solution {
    func countEven(_ num: Int) -> Int {
        var result = 0
        for i in 1...num {
            var tmp = 0
            for s in String(i) {
                tmp += Int(String(s))!
            }
            if (tmp % 2 == 0) {
                result += 1
            }
        }
        return result
    }
}
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