Answer Happy

Typical Sudokus you can find for example in newspapers are 9 by 9 grids divided into nine 3 by 3 sub-grids (aka blocks). Some of the cells in the grid are fill in with one integer each, from {1,2,..., 9}. The other cells in the grid are empty. 00 2 8 6 7 4 1 5 9 7 3 2 4 8 3 415 13 9 5 7 9 83 17 The goal then is to fill in the empty cells such that each block, each column and each row contain exactly the number from {1,2,...,9}
41151763 나 나 928 863259417 729481635 5 6 19 76342 8 8 2 453 817 611 3 7612458 589 13 26 9 51874 95 4 6.5 784293 94 83 1 71256 The general problem Sudoku can be described as follows. Input: A gridas (nº x n?)-array, divided into blocks of (n x n)-squares, some of the array entries contain each an integer each, from {1,2,...,n?} Question: Can empty cells in the grid be completed such that each row, each column, and each block contains each integer from {1, 2, ..., ne?}? Prove that Sudoku is in NP.