Question

C PROGRAMMING

You must write a C program to check the validity of a Sudoku solution. Follow the link to know more about Sudoku: https://www.bigfishgames.com/blog/how-to-solve-sudoku-puzzles-quickly-andreliably/
You must at least do the following:
1- Ask the user to provide a minimum of first two rows of the Sudoku grid. For the rest of the entries, you should use random number generator.

2- Use appropriate logic to make sure random number generator generates distinct set of valid integers!

3- It should be a console-based, yet convenient and intuitive user interface to get first two rows of the grid from the user. Use data validation to ensure user enters exactly nine integers without entering an invalid data, for example, non-numeric values or integers less than 1 or greater than 9.

4- You should use multi-dimensional array to represent the grid.

5- Once the grid is fully populated, display the grid in a 9 x 9 matrix format, followed by your decision of whether it forms a valid Sudoku solution or not.

6- As a test case, your code should prove that the following is a valid Sudoku solution.

OUTPUT SHOULD BE LIKE THIS

2873-6459 14 62958 37 935478261 852134796 794652318 613789542 428963-75 379521684 5 618 4 7923 5 3 4 6 78 91 2 6 7 2 1 9 5 3 4 8 1 9 8 3 4 2 5 6 7 8 5 9 7 6 1 4 3 4 2 6 8 5 3 7 9 1 7 1 3 9 2 485 6 9 6 1 5 3 7 2 8 4 2 87 4 1 9 6 3 5 3 4 5 2 8 6 1 79 It is a valid solution Enter row 1 of your Sudoku grid Use Space/Tab/Return key to enter the next values and press 'Return' after entering nine integers. Remember, to make a valid row of Sudoku grid, all integers should be distinct and range from 1 to 9 3 4 5 67 8 7 1 1 Enter row 2 of your Sudoku grid Use Space/Tab/Return key to enter the next values and press Return' after entering nine integers. Remember, to make a valid row of Sudoku grid, all integers should be distinct and range from 1 to 9 2 1 2 3 4 5 6 7 8 9 -Sudoku Grid---- 3 45 6 78 71 1 1 2 3 4 5 6 7 89 6 9 85 2 4 1 3 7 8 6 9 4 1 7532 8 4 3 7 26 5 1 9 2 74 3 9 1 5 6 8 4 8 2 6 75 3 91 3 7 9 5 6 4 2 1 8 7 2 6 1 3 8 9 5 4 It is an invalid solution Process returned e (0xe) execution time 217.056 s Press any key to continue

Answer 1

Program:

//Header files

#include<stdio.h>

#include<stdlib.h>

#include<time.h>

//Function to return 1 if sudoku grid is valid and 0 otherwise

int checkWin(int b[9][9])

{

int i, j, k, l, m, n;

//Invalid if any value is not from 1 to 9

for(i = 0; i < 9; i++)

for( j = 0; j < 9; j++)

if(b[i][j] < 1 || b[i][j] > 9)

return 0;

//Invalid if any value repeats in the row

for(i = 0; i < 9; i++)

for( j = 0; j < 9; j++)

for(k = 1; k < j; k++)

if(b[i][j] == b[i][k])

return 0;

//Invalid if any value repeats in the column

for(j = 0; j < 9; j++)

for(i = 0; i < 9; i++)

for(k = 1; k < i; k++)

if(b[i][j] == b[k][j])

return 0;

//Invalid if any value repeats in the block

for(i = 0; i < 9; i++)

for(j = 0; j < 9; j++)

{

m = (int)(i / 3) * 3;

n = (int)(j / 3) * 3;

for(k = m; k < m + 3; k++)

for(l = n; l < n + 3; l++)

if((i != k || j != l) && (b[i][j] == b[k][l]))

return 0;

}

//Otherwise, valid

return 1;

}

//Function to print the result accordingly

void printResult(int result)

{

if(result == 1)

printf("It is a valid solution.\n");

else

printf("It is an invalid solution.\n");

}

//Fucntion to display the grid

void displayGrid(int arr[9][9])

{

int i, j;

printf("\n-------------Sudoku Grid-------------");

for(i = 0; i < 9; i++)

{

printf("\n");

for(j = 0; j < 9; j++)

printf(" %d", arr[i][j]);

}

printf("\n\n");

}

//main() begins

int main(void)

{

int i, j, k;

//Test case grid

int arr[9][9] = {5, 3, 4, 6, 7, 8, 9, 1, 2,

6, 7, 2, 1, 9, 5, 3, 4, 8,

1, 9, 8, 3, 4, 2, 5, 6, 7,

8, 5, 9, 7, 6, 1, 4, 2, 3,

4, 2, 6, 8, 5, 3, 7, 9, 1,

7, 1, 3, 9, 2, 4, 8, 5, 6,

9, 6, 1, 5, 3, 7, 2, 8, 4,

2, 8, 7, 4, 1, 9, 6, 3, 5,

3, 4, 5, 2, 8, 6, 1, 7, 9};

displayGrid(arr);

printResult(checkWin(arr));

//Get 2 rows of input

for(i = 0; i < 2; i++)

{

printf("Enter row %d of your Sudoku grid\n", i + 1);

printf("Use Space/Tab/Return key to enter the next values\n");

printf("and press \'Return\' after entering nine integers.\n");

printf("Remember, to make a valid row of Sudoku grid,\n");

printf("all integers should be distinct and range from 1 to 9\n");

for(j = 0; j < 9; j++)

scanf("%d", &arr[i][j]);

}

//Generate remaining rows

srand(time(0));

for(i = 2; i < 9; i++)

for(j = 0; j < 9; j++)

{

arr[i][j] = 1 + rand() % 9;

//Repeat the element if it is already present in that row

for(k = 0; k < j; k++)

if(arr[i][j] == arr[i][k])

j--;

}

displayGrid(arr);

printResult(checkWin(arr));

}

Output: (User input is in bold)

-------------Sudoku Grid-------------
5 3 4 6 7 8 9 1 2
6 7 2 1 9 5 3 4 8
1 9 8 3 4 2 5 6 7
8 5 9 7 6 1 4 2 3
4 2 6 8 5 3 7 9 1
7 1 3 9 2 4 8 5 6
9 6 1 5 3 7 2 8 4
2 8 7 4 1 9 6 3 5
3 4 5 2 8 6 1 7 9

It is a valid solution.
Enter row 1 of your Sudoku grid
Use Space/Tab/Return key to enter the next values
and press 'Return' after entering nine integers.
Remember, to make a valid row of Sudoku grid,
all integers should be distinct and range from 1 to 9
3 4 5 6 7 8 7 1 1
Enter row 2 of your Sudoku grid
Use Space/Tab/Return key to enter the next values
and press 'Return' after entering nine integers.
Remember, to make a valid row of Sudoku grid,
all integers should be distinct and range from 1 to 9
1 2 3 4 5 6 7 8 9

-------------Sudoku Grid-------------
3 4 5 6 7 8 7 1 1
1 2 3 4 5 6 7 8 9
2 6 5 8 3 1 4 9 7
4 3 8 5 7 2 6 9 1
1 9 2 4 5 7 6 8 3
7 5 9 4 8 6 2 3 1
8 5 2 3 4 1 7 9 6
6 5 3 1 4 8 2 7 9
7 3 1 8 5 6 4 2 9

It is an invalid solution.

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