摘要：
N-QueensThe n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other.Given an integer n, retu... 阅读全文
摘要：
Valid SudokuDetermine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules.The Sudoku board could be partially filled, where empty cells are... 阅读全文