#include <stdio.h>
int f[9] = {0}, copy[9][9] = {0};
int t1[9][9] = {0}, t2[9][9] = {0}, t3[9][9] = {0};
int board[9][9] = {{8, 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}};
int ifans = 0;
void f1()
{
    printf("|");
    for (int i = 0; i < 23; i++)
    {
        printf("-");
    }
    printf("|\n");
}
void operate()
{
    for (int i = 0; i < 9; i++)
    {
        if (i % 3 == 0)
        {
            f1();
        }
        printf("| ");
        for (int j = 0; j < 9; j++)
        {
            if (j % 3 == 0 && j)
            {
                printf("| ");
            }
            printf("%d ", board[i][j]);
        }
        printf("|\n");
    }
    f1();
}
int judge()
{
    for (int i = 0; i < 9; i++)
    {
        for(int j = 0; j < 9; j++)
        {
            if (board[i][j])
            {
                t1[i][board[i][j] - 1]++;
                t2[j][board[i][j] - 1]++;
                t3[(i / 3) * 3 + j / 3][board[i][j] - 1]++;
            }
        }
    }
    for (int i = 0; i < 9; i++)
    {
        for (int num = 0; num < 9; num++)
        {
            if (t1[i][num] > 1)
            {
                printf("False:Invalid initial Sudoku matrix!\n");
                printf("      The number %d in the row %d has been used!\n", num + 1, i + 1);
                printf("No solution!");
                return 0;
            }
            else if (t2[i][num] > 1)
            {
                printf("False:Invalid initial Sudoku matrix!\n");
                printf("      The number %d in the col %d has been used!\n", num + 1, i + 1);
                printf("No solution!");
                return 0;
            }
            else if (t3[i][num] > 1)
            {
                printf("False:Invalid initial Sudoku matrix!\n");
                printf("      The number %d in the block %d has been used!\n", num + 1, i + 1);
                printf("No solution!");
                return 0;
            }
        }
    }
    printf("True:Valid initial Sudoku matrix!\n");
    return 1;
}
void fill(int x, int y)
{
    int num;
    if (x == 9 && y == 0)
    {
        printf("The solution of Sudoku matrix:\n");
        operate();
        ifans = 1;
    }
    else
    {
        if (copy[x][y])
        {
            if (y == 8)
            {
                fill(x + 1, 0);
                if (x == 0 && y == 0 && ifans == 0)
                {
                    printf("No solution!");
                }
                return;
            }
            else{
                fill(x, y + 1);
                if (x == 0 && y == 0 && ifans == 0)
                {
                    printf("No solution!");
                }
                return;
            }
        }
        else
        {
            for(num = 1; num <= 9; num++)
            {
                if (t1[x][num - 1] == 0 && t2[y][num - 1] == 0 && t3[(x / 3) * 3 + y / 3][num - 1] == 0)
                {
                    board[x][y] = num;
                    t1[x][num - 1] = 1;
                    t2[y][num - 1] = 1;
                    t3[(x / 3) * 3 + y / 3][num - 1] = 1;
                    if (y == 8)
                    {
                        // operate();
                        fill(x + 1, 0);
                        board[x][y] = 0;
                        t1[x][num - 1] = 0;
                        t2[y][num - 1] = 0;
                        t3[(x / 3) * 3 + y / 3][num - 1] = 0;
                    }
                    else{
                        // operate();
                        fill(x, y + 1);
                        board[x][y] = 0;
                        t1[x][num - 1] = 0;
                        t2[y][num - 1] = 0;
                        t3[(x / 3) * 3 + y / 3][num - 1] = 0;
                    }
                }
            }
            if (x == 0 && y == 0 && ifans == 0)
            {
                printf("No solution!");
            }
            return;
        }
    }
}
int main()
{
    printf("The original Sudoku matrix:\n");
    operate();
    for (int i = 0; i < 9; i++)
    {
        for (int j = 0; j < 9; j++)
        {
            copy[i][j] = board[i][j];
        }
    }
    if(judge())
    {
        fill(0,0);
    }
}