Description:

Your task, should you choose to accept it, is to make a function that checks to see if a 9x9 matrix of integers represents a completed sudoku puzzle. For more information regarding sudokus, refer to the wikipedia page.

The function will return true only when it's a completed sudoku puzzle. A value of 0 refers to a blank entry.

Example:

   input = [ 8 2 4 9 5 3 6 7 1
             6 3 5 8 1 7 9 2 4
             7 1 9 6 2 4 8 5 3
             5 8 7 2 9 1 3 4 6
             1 4 2 7 3 6 5 8 9
             3 9 6 4 8 5 2 1 7
             2 6 1 5 4 9 7 3 8
             4 7 8 3 6 2 1 9 5
             9 5 3 1 7 8 4 6 2 ];
   answer = true;

   input = [ 8 2 4 9 5 3 6 7 1
             6 3 5 8 1 7 9 2 4
             7 1 9 0 2 4 8 5 3
             5 8 7 2 9 1 3 4 6
             1 4 2 7 3 0 5 8 9
             3 9 6 4 8 5 2 1 7
             2 6 1 5 4 9 7 3 8
             4 7 8 3 6 2 1 9 5
             9 5 3 1 7 8 4 6 2 ];
    answer = false;