SUDOKU
Write a number from 1 to 9 into each empty square in the grid so that every number from 1 to 9 appears exactly once in each horizontal row, each vertical column, and each 3×3 block.
6
2
1
7
6
7
3
2
3
5
7
7
9
5
9
1
4
5
1
4
9
3
2
4
5
1
* Easy