eight queens puzzle

1 definition found

eight queens puzzle - Free On-line Dictionary of Computing (26 May 2007) :

  eight queens puzzle
  8 queens problem
  8 queens puzzle
  eight queens problem
  
     <algorithm> A puzzle in which one has to place eight queens on
     a chessboard such that no queen is attacking any other,
     i.e. no two queens occupy the same row, column or diagonal.
     One may have to produce all possible such configurations or
     just one.
  
     It is a common students assignment to devise a program to
     solve the eight queens puzzle.  The brute force algorithm
     tries all 64*63*62*61*60*59*58*57 = 178,462,987,637,760
     possible layouts of eight pieces on a chessboard to see which
     ones meet the criterion.  More intelligent algorithms use the
     fact that there are only ten positions for the first queen
     that are not reflections of each other, and that the first
     queen leaves at most 42 safe squares, giving only
     10*42*41*40*39*38*37*36 = 1,359,707,731,200 layouts to try,
     and so on.
  
     The puzzle may be varied with different number of pieces and
     different size boards.
  
     [Best algorithm?]
  
     (1999-07-28)