/*
  https://puzzles9.com/puzzles/number-sequence-puzzles-with-answers/
  Puz1057
  """
  2 8
  4 9
  3 7
  6 9
  6 8
  3 ?

  Answer : 4
  Calculate the difference of numbers in each row. it follows a particular sequence 
  like 6,5,4,3,2,1.

  8 – 2 = 6
  9 – 4 = 5
  7 – 3 = 4
  9 – 6 = 3
  8 – 6 = 2
  4 – 3 = 1

  So, answer is 4.
  """

  Since there are both "6 9" and "6 8" in the data, we cannot use the simple representation.
  Let's test the extended variant:
    0 0 2 8
    2 8 4 9
    4 9 3 7 
    3 7 6 9
    6 9 6 8
    6 8 3 ?

  Nope. 

  However, it works if we add an index to each row (1..6):
     1  2 8
     2  4 9
     3  3 7
     4  6 9
     5  6 8
     6  3 ?

  maxCount = 3
  code = ((B + 7) - A) = [[[1,2],8],[[2,4],9],[[3,3],7],[[4,6],9],[[5,6],8]] = [[6,3] = 4]



*/

data(puz1057,Data,Vars,Unknown,Ops,Constants,MaxC) :-
  % Data = [
  %         [[0,0,2],8],
  %         [[2,8,4],9],
  %         [[4,9,3],7],
  %         [[3,7,6],9],
  %         [[6,9,6],8]
  %        ],
  Data = [
          [[1,2],8],
          [[2,4],9],
          [[3,3],7],
          [[4,6],9],
          [[5,6],8]
         ],
  Unknown = [6,3],
  Vars = ["A","B","C"],
  Ops = new_map([infix=["+","-"] ]),
  Constants = 1..10,
  MaxC = 3.