please make sure the code works /* * Your goal in this exercise is to practice recursion
Question:
/*
* Your goal in this exercise is to practice recursion and
* to see how a properly written recursive solution can
* take care of fairly complicated tasks with a few lines
* of (well thought out) code.
*
* We will be solving Sudoku puzzles. In case you have never
* solved or seen a Sudoku, you can learn more about them
* here:
*
* https://en.wikipedia.org/wiki/Sudoku
*
* Your task is to write a function that takes an input
* Sudoku in the form of a 9x9 array of integers. the
* array will have a few entries filled with numbers in
* [1, 9], and the remaining entries set to zero.
*
* For the example in the wiki, the input array will
* be
*
* 5 3 0 0 7 0 0 0 0
* 6 0 0 1 9 5 0 0 0
* 0 9 8 0 0 0 0 6 0
* 8 0 0 0 6 0 0 0 3
* 4 0 0 8 0 3 0 0 1
* 7 0 0 0 2 0 0 0 6
* 0 6 0 0 0 0 2 8 0
* 0 0 0 4 1 9 0 0 5
* 0 0 0 0 8 0 0 7 9
*
* Your code should find the values that correctly
* complete the Sudoku.
*
* As a brief reminder, a correctly solved Sudoku is
* one in which there are no repeated digits in any
* row, any column, or any of the 3x3 sub-arrays that
* make up the large 9x9 grid. Another way to think
* about it is, every row, column, and 3x3 subgrid
* uses all of the different digits.
*
* How to solve this?
*
* * RECURSIVELY!
*
* (hint) - Solving a Sudoku with N unknown values
* may involve trying something, then solving an
* easier Sudoku problem.
*
* * How to approach this?
*
* - As noted in class:
* a) Determine the base case(s)
* b) Figure out the recursive case
* c) Determine what needs to happen to
* the solution for the entire problem
* is returned once the recursion hits
* the base case(s)
*
* - Conditions on the input Sudoku
* - It will have AT LEAST ONE DIGIT in each
* 3x3 subgrid. Likely there will be several
* 3x3 subgrids with several digits already
* set to some value.
*
* - Conditions on your solution
* - It should return a solution if there
* exists one.
* - If no solution can be found, return the
* original input array
* - If multiple solutions exist, any one of
* them is valid
*
* - Can I use helper functions?
* - Yes, by all means!
*
* - Can I add extra libraries?
* - No, they won't be needed.
*
* - Can I change the 'print_sudoku()' function?
* - Please don't, we may need it for testing!
*
* (c) F. Estrada, March 2019
*/
#include
#include
#include
void print_sudoku(int sudoku[9][9])
{
printf(\"The Sudoku contains: \");
for (int j=0; j9;>
{
for (int i=0; i
{
printf(\"%d \",sudoku[j][i]);
}
printf(\" \");
}
}
int check_sudoku(int sudoku[9][9])
{
/*
* This function checks whether a Sudoku is properly
* solved. That means that each row, column, and
* 3x3 subgrid uses each digit only once.
*
* If *ignores* zeros, so you can use it to check
* that a partial solution is valid
*/
/*****
* TO DO:
* Complete this function
* -- BUT ONLY IF YOU WANT TO!
* Our testing script only checks your Sudoku
* solution, if you want to solve it without
* using this function, or if you want to write
* your own helper functions, that's ok!
* *****/
return 0;
}
int solved(int sudoku[9][9])
{
/*
* This function checks whether a given Sudoku is
* completely solved (it has no zeros, all digits
* are used once per row, column, and sub-grid.
* It returns 1 if the Sudoku is solved, zero
* otherwise
*/
/*****
* TO DO
* Complete this function
* BUT ONLY IF YOU WANT TO!
* You can solve the Sudoku without using this function,
* or you can write a different helper function, whatever
* makes more sense to yoU! our checker won't look at this
* function,
* ****/
return 0;
}
void solve_sudoku(int sudoku[9][9], int depth)
{
/*
* This function solves an input Sudoku, the
* input has a value of 0 for any entries that
* are not yet decided. If no solution exists
* the function returns the input array *exactly
* as it was* when the function was called.
*
* The 'depth' parameter is provided in case you
* want to use it to help debug and trace your
* code. You do not need to use it if you don't
* want to, and the problem can be solved without
* using the depth value at all.
*
* The automated checker won't look at the depth
* either.
*/
/*****
* TO DO:
* Complete this function
*****/
}
#ifndef __testing
int main()
{
// We'll provide you with the same test case
// from the Wiki, so you can check your output.
// But as always, be aware we will test your
// solution on different Sudoku puzzles.
int Sudoku[9][9]={{5, 3, 0, 0, 7, 0, 0, 0, 0},
{6, 0, 0, 1, 9, 5, 0, 0, 0},
{0, 9, 8, 0, 0, 0, 0, 6, 0},
{8, 0, 0, 0, 6, 0, 0, 0, 3},
{4, 0, 0, 8, 0, 3, 0, 0, 1},
{7, 0, 0, 0, 2, 0, 0, 0, 6},
{0, 6, 0, 0, 0, 0, 2, 8, 0},
{0, 0, 0, 4, 1, 9, 0, 0, 5},
{0, 0, 0, 0, 8, 0, 0, 7, 9}};
printf(\"Input puzzle is: \");
print_sudoku(Sudoku);
solve_sudoku(Sudoku,0);
printf(\"Solution is: \");
print_sudoku(Sudoku);
}
#endif
Expert Answer:
