/* 

  Gardner's TWO+TWO=FOUR problem in Picat.

  Via OscaR's GardnerTwoPlusTwo program:
  """
  Martin Gardner Problem:
  
  In this addition problem, each letter stands for a different digit.
  
     T W O
   + T W O
   --------
   F O U R
  
  If T = 7 and the letter O represents an even number, what is the only 
  possible value for W
  """

  This program was created by Hakan Kjellerstrand, hakank@gmail.com
  See also my Picat page: http://www.hakank.org/picat/

*/

 import cp.

main => go.

go =>
  FD = [T,W,O,F,U,R],
  FD:: 0..9,
  T #= 7,
  F #> 0,

  all_different(FD),
  2 * (100*T + 10*W + O) #= 1000*F + 100*O + 10*U + R,
  O mod 2 #= 0,

  solve(FD),

  printf("%d%d%d + %d%d%d == %d%d%d%d  (W=%d)\n",T,W,O, T,W,O, F,O,U,R, W),
  fail,

  
  nl.