Merge pull request #25 from amsharma44/almost_sorted

Almost Sorted solution

almost-sorted.cs

@@ -0,0 +1,99 @@
+using System;
+using System.Linq;
+using System.Collections.Generic;
+using System.Text;
+
+namespace ConsoleApplication
+{
+    class Program
+    {
+        public static void Main(String[] args)
+        {
+            int n = int.Parse(Console.ReadLine());
+            int[] ar = Array.ConvertAll<string, int>(Console.ReadLine().Trim().Split(' '), e => int.Parse(e));
+
+            if(isSorted(ar, n))
+            {
+                Console.WriteLine("yes");
+                return;
+            }
+
+            int a = -1;
+            int b = -1;
+
+            for(int i = 0; i < n - 1; i++)
+            {
+                if(ar[i] > ar[i + 1])
+                {
+                    a = i;
+                    break;
+                }
+            }
+
+            for(int i = n - 1; i > 0; i--)
+            {
+                if(ar[i] < ar[i - 1])
+                {
+                    b = i;
+                    break;
+                }
+            }
+
+            if(a != -1 && b != -1)
+            {
+                int temp = ar[a];
+                ar[a] = ar[b];
+                ar[b] = temp;
+
+                if(isSorted(ar, n))
+                {
+                    Console.WriteLine("yes");
+                    Console.WriteLine($"swap {a + 1} {b + 1}");
+                    return;
+                }
+
+                ar[b] = ar[a];
+                ar[a] = temp;
+            }
+
+            int[] nar = new int[n];
+
+            for(int i = 0; i < a; i++)
+            {
+                nar[i] = ar[i];
+            }
+
+            for(int i = 0; i <= b - a; i++)
+            {
+                nar[a + i] = ar[b - i];
+            }
+
+            for(int i = b + 1; i < n; i++)
+            {
+                nar[i] = ar[i];
+            }
+
+            if(isSorted(nar, n))
+            {
+                Console.WriteLine("yes");
+                Console.WriteLine($"reverse {a + 1} {b + 1}");
+                return;
+            }
+
+            Console.WriteLine("no");
+        }
+
+        public static bool isSorted(int[] ar, int n)
+        {
+            for(int i = 1; i < n; i++)
+            {
+                if(ar[i] < ar[i - 1])
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+    }
+}