subroutine tsp_dantzig42_order ( dantzig42_order )

!*****************************************************************************80
!
!! tsp_dantzig42_order() returns the ordering for the Dantzig 42 city TSP challenge.
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    15 July 2026
!
!  Author:
!
!    John Burkardt
!
!  Output:
!
!    integer dantzig42_order[42]: the 1-based optimal tour order.
!
  implicit none

  integer dantzig42_order(42)

  dantzig42_order = (/ &
    42, 41, 40, 39, 38, 37, 36, 35, 34, 33, &
    32, 31, 30, 29, 28, 27, 26, 25, 24, 23, &
    22, 21, 20, 19, 18, 17, 16, 15, 14, 13, &
    12, 11, 10,  9,  8,  7,  6,  5,  4,  3, &
     2,  1 /)

  return
end
subroutine tsp_dantzig42_xy ( dantzig42_xy )

!*****************************************************************************80
!
!! tsp_dantzig42_xy() returns the locations for the Dantzig 42 city TSP challenge.
!
!  Discussion:
!
!    The original values 
!
!     147.5,  36.0,
!     154.5,  45.0,
!
!    were adjusted to 
!
!     147.0,  36.0,
!     154.0,  45.0,
!
!    so that all coordinates are integers.
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    21 July 2026
!
!  Author:
!
!    John Burkardt
!
!  Output:
!
!    real ( kind = rk8 ) tsp_dantzig42_xy(42,2): the x and y coordinates of the cities.
!
  implicit none

  integer, parameter :: rk8 = kind ( 1.0D+00 )

  real ( kind = rk8 ) dantzig42_xy(42,2)
!
!  Excuse this monstrous "tranpose(reshape())", caused by the fact that
!  the data is by rows, but Fortran prefers columns.
!
  dantzig42_xy = transpose ( reshape ( (/ &
      170.0,  85.0, &
      166.0,  88.0, &
      133.0,  73.0, &
      140.0,  70.0, &
      142.0,  55.0, &
      126.0,  53.0, &
      125.0,  60.0, &
      119.0,  68.0, &
      117.0,  74.0, &
       99.0,  83.0, &
       73.0,  79.0, &
       72.0,  91.0, &
       37.0,  94.0, &
        6.0, 106.0, &
        3.0,  97.0, &
       21.0,  82.0, &
       33.0,  67.0, &
        4.0,  66.0, &
        3.0,  42.0, &
       27.0,  33.0, &
       52.0,  41.0, &
       57.0,  59.0, &
       58.0,  66.0, &
       88.0,  65.0, &
       99.0,  67.0, &
       95.0,  55.0, &
       89.0,  55.0, &
       83.0,  38.0, &
       85.0,  25.0, &
      104.0,  35.0, &
      112.0,  37.0, &
      112.0,  24.0, &
      113.0,  13.0, &
      125.0,  30.0, &
      135.0,  32.0, &
      147.0,  18.0, &
      147.0,  36.0, &
      154.0,  45.0, &
      157.0,  54.0, &
      158.0,  61.0, &
      172.0,  82.0, &
      174.0,  87.0 /), (/ 2, 42 /) ) )

  return
end