DataStructuresAlgorithmsAndComplexityTask2

/*
 * Task 2
 * What is the expected running time of the
 * following C# code? Explain why.
 * Assume the input matrix has size of n * m.
 */

namespace Task2
{
    using System;

    public class Task2
    {
        /// <summary>
        /// Original Code from homework.
        /// </summary>
        public static long CalcCountOriginal(int[,] matrix)
        {
            long count = 0;
            for (int row = 0; row < matrix.GetLength(0); row++)
                if (matrix[row, 0] % 2 == 0)
                    for (int col = 0; col < matrix.GetLength(1); col++)
                        if (matrix[row, col] > 0)
                            count++;
            return count;
        }

        /// <summary>
        /// Test code.
        /// </summary>
        private static void Main()
        {
            int[,] matrix = new int[,]
            {
                { 1, 2, 4, -5, 3 },
                { 122, 33, -56, 22, 3 },
                { 1, 2, 4, -5, 3 },
                { 122, 33, -56, 22, 3 },
            };

            Console.WriteLine(CalcCountOriginal(matrix));
        }

        /*
         * Runing time of this code is: O(n * m)
         * Because for every row with first element wich is even
         * we check all columns of row --- odd <-> even is fifty <-> fifty ;)
         * and therefore formula is n/2 * m ---> O(n * m).
         * No improving is available - this is optimal code!
         */
    }
}