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A puzzle in which one has to place eight queens ona 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 orjust one.It is a common students assignment to devise a program tosolve the eight queens puzzle. The brute force algorithmtries all 64*63*62*61*60*59*58*57 = 178,462,987,637,760possible layouts of eight pieces on a chessboard to see whichones meet the criterion. More intelligent algorithms use thefact that there are only ten positions for the first queenthat are not reflections of each other, and that the firstqueen leaves at most 42 safe squares, giving only10*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 anddifferent size boards.[Best algorithm?]