add greedy algorithm

greedy/Greedy.cs

@@ -0,0 +1,99 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ConsoleApplication1
+{
+    class Program
+    {
+        private static int _activityCount;
+        private static int[] _startTimes;
+        private static int[] _finishTimes;
+
+        static void Main(string[] args)
+        {
+            getStarted();
+        }
+
+        public static string Greedy(int[] start, int[] finish)
+        {
+            string a = "1";
+            int i = 0;
+            int n = start.Length;
+
+            for (int m = 1; m < n; m++)
+            {
+                if (start[m] >= finish[i])
+                {
+                    a = a + ", " + (m + 1);
+                    i = m;
+                }
+            }
+            return a;
+        }
+
+        public static void getStarted()
+        {
+            _activityCount = 0;
+            _startTimes = null;
+            _finishTimes = null;
+            Console.WriteLine("Greedy Activity Selector");
+            activityQuestion();
+            Console.WriteLine("Compatible activities: " + Greedy(_startTimes, _finishTimes));
+            Console.WriteLine();
+            getStarted();
+        }
+
+        public static void activityQuestion()
+        {
+            Console.WriteLine("Enter number of activities:");
+            var userInput = Console.ReadLine();
+            if (userInput.ToLower() == "exit") { Environment.Exit(0); }
+            try
+            {
+                _activityCount = Int32.Parse(userInput);
+                startQuestion();
+            }
+            catch
+            {
+                Console.WriteLine("You did not enter a whole number");
+                activityQuestion();
+            }
+        }
+
+        public static void startQuestion()
+        {
+            Console.WriteLine("Enter start times:");
+            var startTimes = Console.ReadLine();
+            if (startTimes.ToLower() == "exit") { Environment.Exit(0); }
+            try
+            {
+                _startTimes = startTimes.Split(new[] { ',', ' ' }, StringSplitOptions.RemoveEmptyEntries).Select(int.Parse).ToArray();
+                finishQuestion();
+            }
+            catch
+            {
+                Console.WriteLine("Invalid format. Separate numbers with a space or comma.");
+                startQuestion();
+            }
+        }
+
+        public static void finishQuestion()
+        {
+            Console.WriteLine("Enter finish times:");
+            var finishTimes = Console.ReadLine();
+            if (finishTimes.ToLower() == "exit") { Environment.Exit(0); }
+            try
+            {
+                _finishTimes = finishTimes.Split(new[] { ',', ' ' }, StringSplitOptions.RemoveEmptyEntries).Select(int.Parse).ToArray();
+            }
+            catch
+            {
+                Console.WriteLine("Invalid format. Separate numbers with a space or comma.");
+                finishQuestion();
+            }
+        }
+    }
+}