import std.math;
+ import std.typecons;
  /*
  We have an array 'arr' of N integers arr[1], arr[2], ..., arr[N].The
-     numbers in the array will be randomly ordered. Your task is to determine if
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+ numbers in the array will be randomly ordered. Your task is to determine if
-     it is possible to get an array sorted in non-decreasing order by performing 
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+ it is possible to get an array sorted in non-decreasing order by performing 
-     the following operation on the given array:
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+ the following operation on the given array:
-         You are allowed to perform right shift operation any number of times.
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+     You are allowed to perform right shift operation any number of times.
-     
-     One right shift operation means shifting all elements of the array by one
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+ One right shift operation means shifting all elements of the array by one
-     position in the right direction. The last element of the array will be moved to
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+ position in the right direction. The last element of the array will be moved to
-     the starting position in the array i.e. 0th index. 
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+ the starting position in the array i.e. 0th index. 
- 
-     If it is possible to obtain the sorted array by performing the above operation
? ----

+ If it is possible to obtain the sorted array by performing the above operation
-     then return true else return false.
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+ then return true else return false.
-     If the given array is empty then return true.
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+ If the given array is empty then return true.
- 
-     Note: The given array is guaranteed to have unique elements.
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+ Note: The given array is guaranteed to have unique elements.
- 
-     For Example:
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+ For Example:
-     
-     >>> move_one_ball([3L, 4L, 5L, 1L, 2L])
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+ >>> move_one_ball([3L, 4L, 5L, 1L, 2L])
-     true
+ true
-     Explanation: By performin 2 right shift operations, non-decreasing order can
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+ Explanation: By performin 2 right shift operations, non-decreasing order can
-                  be achieved for the given array.
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+              be achieved for the given array.
-     >>> move_one_ball([3L, 5L, 4L, 1L, 2L])
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+ >>> move_one_ball([3L, 5L, 4L, 1L, 2L])
-     false
+ false
-     Explanation:It is not possible to get non-decreasing order for the given
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+ Explanation:It is not possible to get non-decreasing order for the given
-                 array by performing any number of right shift operations.
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+             array by performing any number of right shift operations.
-                 
-     
  */
  bool move_one_ball(long[] arr)