HackerRank - Alternating Characters - https://www.hackerrank.com/challenges/alternating-characters

AlternatingCharacters.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AlternatingCharacters
{
    /*
     * Alternating Characters
     * 
     * https://www.hackerrank.com/challenges/alternating-characters
     * 
     * 
     */
    class Program
    {
        static void Main(string[] args)
        {
            string s1 = Console.ReadLine();
            int n = Convert.ToInt16(s1); 

            for(int i=0;i<n;i++)
            {
                string s = Console.ReadLine();
                Console.WriteLine(countDeletion(s)); 
            }
        }

        /*
         * string.Length >= 1
         */
        public static int countDeletion(string s)
        {
            if (s == null || s.Length == 0)
                return 0;

            int count = 0; 
            for(int i=1; i< s.Length; i++)
            {
                if (s[i] == s[i - 1])
                    count++; 
            }

            return count; 
        }
    }
}