Su-Su-Sudoku
Su-Su-Sudoku
By now, everyone has played Sudoku: you’re given a 9-by-9 grid of boxes which you are to fill in with the digits 1 through 9 so that
every row has all nine digits,
every column has all nine digits, and
all nine 3-by-3 subgrids have all nine digits.
To start the game you are given a partially completed grid and are asked to fill in the remainder of the boxes. One such puzzle is shown below.
In this problem, you will be given Sudoku grids which you have nearly completed; indeed you’ve filled in every box except five. You are asked to complete the grid, or determine that it’s impossible. (You might have already made an error!)
Input data
The first line of input will contain a positive integer indicating the number of test cases to follow. Each test case will be a nearly completed Sudoku grid consisting of 9 lines, each containing 9 characters from the set of digits 0 through 9. There will be exactly five 0’s in each test case, indicating the five unfilled boxes.
Output data
Output for each test case should be either
Could not complete this grid.
if it is impossible to complete the grid according to the rules of the game, or the completed grid, in the form given below. (There are no blank spaces in the output.) If there is a way to complete the grid, it will be unique. Separate test cases with a blank line.
Examples
2 481253697 267948105 539671204 654389712 908704563 173562849 702136958 315897426 896425371 481253697 267948105 539671284 654289710 908704562 173562849 702136958 315897426 896425371
481253697 267948135 539671284 654389712 928714563 173562849 742136958 315897426 896425371 Could not complete this grid.