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queens problem




chess queen
A famous chess problem that asks in how many ways eight queens can be placed on a chessboard so that no two attack each other. The generalized problem, to find how many ways n queens can be placed on an n × n board so that no two attack each other, was first posed by Franz Nauck in 1850. In 1874 GŁnther and Glaisher described methods for solving this problem based on determinants. The number of distinct solutions, not counting rotations and reflections, for board sizes of 1 × 1 to 10 × 10 is 1, 0, 0, 1, 2, 1, 6, 12, 46, and 92, respectively. The 6 × 6 puzzle, for which there is a solitary unique solution, was sold in Victorian London in the form of a wooden board with 36 holes into which pins were placed, for one penny.


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   • GAMES AND PUZZLES