Testing the Sudoku Solver

Now that we have implemented the Sudoku solver algorithm using backtracking, let's test it with some sample puzzles.

To test the solver, we will create a few Sudoku puzzles with different levels of difficulty. We will pass these puzzles to the solveSudoku function and check if the solver returns the correct solution.

Here's an example of a sample Sudoku puzzle:

1vector<vector<int>> puzzle = {
2  {5, 3, 0, 0, 7, 0, 0, 0, 0},
3  {6, 0, 0, 1, 9, 5, 0, 0, 0},
4  {0, 9, 8, 0, 0, 0, 0, 6, 0},
5  {8, 0, 0, 0, 6, 0, 0, 0, 3},
6  {4, 0, 0, 8, 0, 3, 0, 0, 1},
7  {7, 0, 0, 0, 2, 0, 0, 0, 6},
8  {0, 6, 0, 0, 0, 0, 2, 8, 0},
9  {0, 0, 0, 4, 1, 9, 0, 0, 5},
10  {0, 0, 0, 0, 8, 0, 0, 7, 9}
11};