Inspiration

MHL sessions

What it does

c++ code that solve sudoku game

How we built it

using c++

Challenges we ran into

backtracking

Accomplishments that we're proud of

it successfully worked

What we learned

logic building

What's next for Sudoku Solver

I'll create a user interface and the deploy.

here's the code

#include <bits/stdc++.h>
using namespace std;
#define UNASSIGNED 0
#define N 9
bool FindUnassignedLocation(int grid[N][N],int& row, int& col);
bool isSafe(int grid[N][N], int row,int col, int num);
bool SolveSudoku(int grid[N][N])
{
    int row, col;
    if (!FindUnassignedLocation(grid, row, col))
        return true;
    for (int num = 1; num <= 9; num++) 
    {

        if (isSafe(grid, row, col, num)) 
        {
            grid[row][col] = num;

            if (SolveSudoku(grid))
                return true;
            grid[row][col] = UNASSIGNED;
        }
    }

    return false;
}

bool FindUnassignedLocation(int grid[N][N],int& row, int& col)
{
    for (row = 0; row < N; row++)
        for (col = 0; col < N; col++)
            if (grid[row][col] == UNASSIGNED)
                return true;
    return false;
}

bool UsedInRow(int grid[N][N], int row, int num)
{
    for (int col = 0; col < N; col++)
        if (grid[row][col] == num)
            return true;
    return false;
}

bool UsedInCol(int grid[N][N], int col, int num)
{
    for (int row = 0; row < N; row++)
        if (grid[row][col] == num)
            return true;
    return false;
}

bool UsedInBox(int grid[N][N], int boxStartRow,int boxStartCol, int num)
{
    for (int row = 0; row < 3; row++)
        for (int col = 0; col < 3; col++)
            if (grid[row + boxStartRow]
                    [col + boxStartCol] ==
                                       num)
                return true;
    return false;
}

bool isSafe(int grid[N][N], int row,int col, int num)
{

    return !UsedInRow(grid, row, num)
           && !UsedInCol(grid, col, num)
           && !UsedInBox(grid, row - row % 3,
                         col - col % 3, num)
           && grid[row][col] == UNASSIGNED;
}
void printGrid(int grid[N][N])
{
    for (int row = 0; row < N; row++) 
    {
        for (int col = 0; col < N; col++)
            cout << grid[row][col] << " ";
        cout << endl;
    }
}
int main()
{

    int grid[N][N] = { { 3, 0, 6, 5, 0, 8, 4, 0, 0 },
                       { 5, 2, 0, 0, 0, 0, 0, 0, 0 },
                       { 0, 8, 7, 0, 0, 0, 0, 3, 1 },
                       { 0, 0, 3, 0, 1, 0, 0, 8, 0 },
                       { 9, 0, 0, 8, 6, 3, 0, 0, 5 },
                       { 0, 5, 0, 0, 9, 0, 6, 0, 0 },
                       { 1, 3, 0, 0, 0, 0, 2, 5, 0 },
                       { 0, 0, 0, 0, 0, 0, 0, 7, 4 },
                       { 0, 0, 5, 2, 0, 6, 3, 0, 0 } };
    if (SolveSudoku(grid) == true)
        printGrid(grid);
    else
        cout << "solution does't exists";

    return 0;
}