/*
  From 
  Muhammad Zain Sarwar: "People With an IQ of 120+ Can Solve This Puzzle — Finding the Missing Number!"
  https://medium.com/puzzle-sphere/people-with-an-iq-of-120-can-solve-this-puzzle-finding-missing-numbers-47c2a3117435
  """
  Find missing number?

     7        2      5
   9 2 8    7 8 4  6 ? 9

      A
    B D C 
  """

  A solution:

   B*C = AD

   9*7 = 72
   7*4 = 28
   6*9 = 54  -> ? = 4

  To solve this with symbolic regression, we thus need to_num2(A,B) -> AB.
  See below for some other approaches (and answers).
 

  AllGood:
  [program = C - to_num2(A,C) + B * C,res = 4,count = 739]
  [program = C * B + (C - to_num2(A,C)),res = 4,count = 714]
  [program = B * C + (C - to_num2(A,C)),res = 4,count = 702]
  [program = C - to_num2(A,C) + C * B,res = 4,count = 256]
  [program = to_num2(B - A - B - C,to_num2(C,C * B)),res = 4,count = 201]
  [program = C * B - to_num2(A,C - C),res = 4,count = 133]
  [program = A * C - A * B + B * (C - A),res = 39,count = 29]
  [program = B * C - to_num2(A,C - C),res = 4,count = 6]
  [program = to_num2(C - (C + A),C * B),res = 4,count = 1]
  [program = to_num2(C - (A + C),C * B),res = 4,count = 1]

  resultMap = [4 = 9,39 = 1]

  C - to_num2(A,C) + B * C:  8 - 78 + 9*8 = 2 ;  4 - 24 + 7*4 = 8  ;  9 - 59 + 6*9 = 4


  Without to_num2 (and no constants) we get some other answers, e.g. -8 and 32:

  AllGood:
  [program = (B - C) * (C - A) - (A - C),res = -8,count = 1]

  resultMap = [-8 = 1]

  AllGood:
  [program = (A - C - (C - A)) * (C - C - C + A),res = 32,count = 71]
  [program = (A - C) * (A - C - (C - A)),res = 32,count = 37]
  [program = (C - C - C + A) * (A - C - (C - A)),res = 32,count = 31]
  [program = (A - C - (C - A)) * (A - C),res = 32,count = 2]

  resultMap = [32 = 4]



  Without to_num2/2 and constant 10:

  AllGood:
  [program = C * B - A * 10,res = 4,count = 308]
  [program = C * B - 10 * A,res = 4,count = 159]

  resultMap = [4 = 2]



*/
data(missing_number6,Data,Vars,Unknown,Ops,Constants,MaxSize,Params) :-

  Data = [ [[7,9,8],2],
           [[2,7,4],8]
          ],
  % Ops = [+,-,*,to_num2],
  Ops = [+,-,*],  
  Unknown = [5,6,9],
  Vars = "ABC",
  Constants = [], % No constants
  MaxSize = 11,
  Params = new_map([
                     init_size=1000,
                     num_gens=1000,
                     show_only_good=false
                   ]).