using System;

using System.Collections.Generic;

​

public class Program

{

    private static string[] months = new [] { "JAN", "FEB", "MAR", "APR", "MAY", "JUN", "JUL", "AUG", "SEP", "OCT", "NOV", "DEC", "XXX" };

    private static Dictionary<string,int> monthsDictionary = new Dictionary<string,int>();

    public static void Main()

    {

        const int max = 10000000;

        var random = new Random();

        var start = DateTime.Now;

        for(var count=0; count<max; count++) {

            var index = random.Next(0,12);

            var month = months[index];

            var monthNumber = monthAbbreviationToInt(month);

            //Console.WriteLine($"{month} {monthAbbreviationToInt(month)}");

        }

​

        Console.WriteLine(DateTime.Now.Subtract(start).Milliseconds);

        loadMonthsDictionary();

        start = DateTime.Now;

        for(var count=0; count<max; count++) {

            var index = random.Next(0,11);

            var month = months[index];

            var monthNumber = getMonthNumber(month);

            //Console.WriteLine($"{month} {getMonthNumber(month)}");

        }

​

        Console.WriteLine(DateTime.Now.Subtract(start).Milliseconds);

    }

​

    private static int monthAbbreviationToInt(string monthAbbreviation) {

        switch (monthAbbreviation.ToLower()) {

            case "jan": return 1;

            case "feb": return 2;

            case "mar": return 3;

            case "apr": return 4;

            case "may": return 5;

            case "jun": return 6;

            case "jul": return 7;

            case "aug": return 8;

            case "sep": return 9;

            case "oct": return 10;

            case "nov": return 11;

            case "dec": return 12;

            default: return 0;

        }

    }

    private static int getMonthNumber(string monthAbbreviation) {

        var key = monthAbbreviation;

        if(monthsDictionary.ContainsKey(key)) {

            return monthsDictionary[key];

        }

        return 0;

    }

    private static void loadMonthsDictionary() {

        for(var index=0; index < months.Length; index++) {

            var key = months[index];

            monthsDictionary[key] = index+1;

        }

    }

}