Find Numbers with Even Number of Digits

Description

Given an array nums of integers, return how many of them contain an even number of digits.

 

Example 1:

Input: nums = [12,345,2,6,7896]
Output: 2
Explanation: 
12 contains 2 digits (even number of digits). 
345 contains 3 digits (odd number of digits). 
2 contains 1 digit (odd number of digits). 
6 contains 1 digit (odd number of digits). 
7896 contains 4 digits (even number of digits). 
Therefore only 12 and 7896 contain an even number of digits.

Example 2:

Input: nums = [555,901,482,1771]
Output: 1 
Explanation: 
Only 1771 contains an even number of digits.

 

Constraints:

• 1 <= nums.length <= 500
• 1 <= nums[i] <= 10^5

Solution(javascript)

/**
 * @param {number[]} nums
 * @return {number}
 */
var findNumbers = function(nums) {
    const isEven = (num) => {
        let count = 0
        while(num > 0) {
            num = Math.floor(num / 10)
            count += 1
        }
        return count % 2 === 0
    }
    return nums.reduce((acc, num) => isEven(num) ? acc+ 1: acc, 0)
};