1295-FindNumbersWithEvenNumberOfDigits.go

package main

// 1295. Find Numbers with Even Number of Digits
// 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

import "fmt"

func findNumbers(nums []int) int {
    res := 0
    getLevel := func(n int) int {
        res := 0
        for n > 0 {
            n = n / 10
            res++
        }
        //fmt.Println(res)
        return res
    }
    for _, v := range nums {
        if getLevel(v) % 2 == 0 {
            res++
        }
    }
    return res
}

func main() {
    // 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.
    fmt.Println(findNumbers([]int{12,345,2,6,7896})) // 2
    // Example 2:
    // Input: nums = [555,901,482,1771]
    // Output: 1 
    // Explanation: 
    // Only 1771 contains an even number of digits.
    fmt.Println(findNumbers([]int{555,901,482,1771})) // 1

    fmt.Println(findNumbers([]int{1,2,3,4,5,6,7,8,9})) // 0
    fmt.Println(findNumbers([]int{9,8,7,6,5,4,3,2,1})) // 0
}