Fill a partially completed 9×9 Sudoku board so that every row, column, and 3×3 box contains the digits 1 through 9 exactly once.
You are given a partially filled Sudoku board. Some cells already contain digits 1 to 9, and empty cells are marked with '.'.
Fill the empty cells so that the board becomes a valid Sudoku solution:
1 to 9 exactly once.1 to 9 exactly once.1 to 9 exactly once.Modify the board in place and return a completed valid board. It is guaranteed that at least one solution exists.
'1' through '9' or '.' for an empty cell.Example 1
Input
[ ["5","3",".",".","7",".",".",".","."], ["6",".",".","1","9","5",".",".","."], [".","9","8",".",".",".",".","6","."], ["8",".",".",".","6",".",".",".","3"], ["4",".",".","8",".","3",".",".","1"], ["7",".",".",".","2",".",".",".","6"], [".","6",".",".",".",".","2","8","."], [".",".",".","4","1","9",".",".","5"], [".",".",".",".","8",".",".","7","9"] ]
Output
[ ["5","3","4","6","7","8","9","1","2"], ["6","7","2","1","9","5","3","4","8"], ["1","9","8","3","4","2","5","6","7"], ["8","5","9","7","6","1","4","2","3"], ["4","2","6","8","5","3","7","9","1"], ["7","1","3","9","2","4","8","5","6"], ["9","6","1","5","3","7","2","8","4"], ["2","8","7","4","1","9","6","3","5"], ["3","4","5","2","8","6","1","7","9"] ]
Explanation
One valid completion is shown. Any correct completed Sudoku board is acceptable.
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