Place queens on an chessboard so that no two queens attack each other (same row, column, or diagonal).
Return all distinct solutions. Each solution is a board configuration where 'Q' and '.' indicate a queen and empty square.
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Place queens on an chessboard so that no two queens attack each other (same row, column, or diagonal).
Return all distinct solutions. Each solution is a board configuration where 'Q' and '.' indicate a queen and empty square.