Program to Reverse the subarray in between given range

// C# code for the above approach

using System;
using System.Collections.Generic;

public class GFG {

  static List<int> SubArrReverse(List<int> arr, int L,
                                 int R)
  {
    int noOfElements = R - L + 1;

    // If only one element present, then
    // return the array
    if (noOfElements == 1) {
      return arr;
    }

    // If only two elements present, then swap
    // both the numbers.
    else if (noOfElements == 2) {
      var temp = arr[L];
      arr[L] = arr[R];
      arr[R] = temp;
      return arr;
    }

    // If more than two elements presents, then
    // swap beginning and ending numbers.
    else {
      // Pointer variable to select the elements
      int i = 0;

      // Swap beginning and ending numbers in given
      // indexes.
      while (i < noOfElements / 2) {
        var temp = arr[L + i];
        arr[L + i] = arr[R - i];
        arr[R - i] = temp;

        // If beginning and ending number are same
        // skip
        if ((i != L + i + 1 && i != R - i - 1)
            && (L + i != L + i + 1
                && R - i != R - i - 1)) {
          temp = arr[L + i + 1];
          arr[L + i + 1] = arr[R - i - 1];
          arr[R - i - 1] = temp;
        }
        i += 2;
      }
      return arr;
    }
  }

  static void Print(List<int> arr)
  {
    foreach(var element in arr)
    {
      Console.Write(element + " ");
    }
  }

  static public void Main()
  {

    // Code
    List<int> arr
      = new List<int>{ 1, 2, 3, 4, 5, 6, 7 };
    int L = 1, R = 5;

    Console.Write("Original Array : ");
    Print(arr);
    Console.WriteLine();

    // Function call
    Console.Write("Sub-Array reverse : ");
    var ans = SubArrReverse(arr, L, R);
    Print(ans);
  }
}

// This code is contributed by lokeshmvs21.