Daily sudoku, New York Times,
November 1, 2023, Difficulty: Hard
Sudoku is a logic-based, combinatorial number-placement puzzle.
The objective is to fill a \(9 \times 9\) grid with digits from 1 to 9 in such
a way that the following statements hold:
• Each row contains exactly one occurrence of each digit
from 1 to 9.
• Each column contains exactly one occurrence of each digit
from 1 to 9.
• Each of the nine \(3 \times 3\) subgrids contains exactly one occur-
rence of each digit from 1 to 9.
For a given not yet finished sudoku grid, determine if there is
a mistake in it.
Note: It is not necessary to check whether the sudoku grid is
solvable.
The input describes the sudoku grid.
The characters ’|’, ’-’ and ’+’ frame the \(3 \times 3\) subgrids.
The character ’.’ represents an empty cell.
All the other characters in the input will be digits from ’1’ to ’9’.
See the examples for clarification.
Output the word GRESKA if there is a mistake in the sudoku board. Otherwise, output the word OK.
| 서브태스크 | 점수 | 설명 |
|---|---|---|
1 | 11점 | It’s possible to determine whether there is a mistake by only checking the first rule. |
2 | 12점 | It’s possible to determine whether there is a mistake by only checking the second rule. |
3 | 13점 | It’s possible to determine whether there is a mistake by only checking the third rule. |
4 | 14점 | No additional constraints. |
+---+---+---+
|52.|...|.81|
|.39|58.|...|
|.8.|.9.|...|
+---+---+---+
|24.|...|1.3|
|1..|43.|86.|
|.63|..7|.24|
+---+---+---+
|...|1.9|35.|
|..8|.74|6..|
|31.|86.|7.9|
+---+---+---+OK+---+---+---+
|3..|6..|..4|
|4.9|8.1|..7|
|..7|.49|6..|
+---+---+---+
|946|157|8.2|
|.2.|3..|745|
|.7.|28.|...|
+---+---+---+
|...|4..|..5|
|8.5|.6.|.2.|
|734|..8|5..|
+---+---+---+GRESKA+---+---+---+
|5..|98.|67.|
|6..|...|.31|
|.2.|613|.4.|
+---+---+---+
|.96|8.2|1.7|
|.28|..5|.9.|
|7.3|19.|6..|
+---+---+---+
|962|.7.|.1.|
|1.5|...|76.|
|.7.|5..|9..|
+---+---+---+GRESKAClarification of the first example:
There is no mistake, so the output is OK.
Clarification of the second example:
There is a mistake in the ninth column: the digit 5 appears twice; and there is also a mistake in the lower
right 3 × 3 subgrid: the digit 5 appears twice.
Clarification of the third example:
There are two mistakes: the digit 2 appears twice in the second column, and the digit 6 appears twice in
the seventh column.