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:
using System;
using System.Collections.Generic;
using System.Text;
namespace LeetCode.AskGif.Easy.Array
{
public class FindNumbersSoln
{
public int FindNumbers(int[] nums)
{
int res = 0;
for (int i = 0; i < nums.Length; i++)
{
if (IsEvenCount(nums[i]))
{
res++;
}
}
return res;
}
private bool IsEvenCount(int num)
{
int count = 0;
while(num != 0)
{
count++;
num = num / 10;
}
return count % 2 == 0;
}
}
}
Time Complexity: O(n) Considering the length of the digit is finite.
Space Complexity: O(1)
Unit Tests:
using LeetCode.AskGif.Easy.Array;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Collections.Generic;
using System.Text;
namespace CodingUnitTest.Easy.Array
{
[TestClass]
public class FindNumbersSolnTests
{
[TestMethod]
public void FindNumbersSoln_First()
{
var arr = new int[] { 12, 345, 2, 6, 7896 };
var output = 2;
var res = new FindNumbersSoln().FindNumbers(arr);
Assert.AreEqual(res, output);
}
[TestMethod]
public void FindNumbersSoln_Second()
{
var arr = new int[] { 555, 901, 482, 1771 };
var output = 1;
var res = new FindNumbersSoln().FindNumbers(arr);
Assert.AreEqual(res, output);
}
}
}
