HackerRank - GemStones - https://www.hackerrank.com/challenges/gem-stones

GemStones.cs

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

namespace Gemstones
{
    /*
     * Gemstones
     * https://www.hackerrank.com/challenges/gem-stones
     * 
     */
    class Program
    {
        static void Main(string[] args)
        {
            string s = Console.ReadLine();
            int n = Convert.ToInt16(s); 

            string[] sA = new string[n]; 
            for(int i=0; i<n;i++)
            {
                sA[i]= Console.ReadLine();                 
            }

            Console.WriteLine(getNumberOfGemElement(sA)); 
        }

        /*
         * string length >=1, <=100
         * only lower-cse Latin letters 'a'-'z'
         * 
         * string array size 1 - 100
         */
        public static int getNumberOfGemElement(string[] s)
        {
            int len = s.Length;

            int[][] countA = new int[len][];

            int Size = 26; 
            for (int i = 0; i < len; i++ )
            {
                countA[i] = new int[Size]; 
            }

            for (int i = 0; i < len; i++)
            {
                string s1 = s[i];
                foreach(char c in s1)
                {
                    countA[i][c - 'a']++; 
                }
            }

            int number = 0;
            for (int i = 0; i < Size; i++)
            {
                bool atLeastOneZero = false; 
                for (int j = 0; j < len; j++)  // bug002 not i++, should be j++; spell error 
                {
                    //if (countA[i][j] == 0)  // bug001 - index out of range 
                    if (countA[j][i] == 0)
                    {
                        atLeastOneZero = true; 
                        break;
                    }                    
                }

                if (!atLeastOneZero)
                    number++; 
            }

            return number; 
        }
    }
}