#include <stdio.h>
#include <stdbool.h>

bool panduan(int board[9][9]) {
    for (int i = 0; i < 9; i++) {
        bool row[10] = { 0 }, col[10] = { 0 }, block[10] = { 0 };
        for (int j = 0; j < 9; j++) {
            if (board[i][j] != 0) {
                if (row[board[i][j]]) {
                    printf("The number %d in row %d has been used!\n", board[i][j], i);
                    return false;
                }
                row[board[i][j]] = true;
            }

            if (board[j][i] != 0) {
                if (col[board[j][i]]) {
                    printf("The number %d in column %d has been used!\n", board[j][i], i);
                    return false;
                }
                col[board[j][i]] = true;
            }

            int blockRow = 3 * (i / 3), blockCol = 3 * (i % 3);
            if (board[blockRow + j / 3][blockCol + j % 3] != 0) {
                if (block[board[blockRow + j / 3][blockCol + j % 3]]) {
                    printf("The number %d in block %d has been used!\n",
                        board[blockRow + j / 3][blockCol + j % 3], (i / 3) * 3 + (i % 3));
                    return false;
                }
                block[board[blockRow + j / 3][blockCol + j % 3]] = true;
            }
        }
    }
    return true;
}
int main()
{
    int board[9][9] = {
        {0, 0, 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}
    };
    if (panduan(board)) 
    {
        printf("True: Valid initial Sudoku matrix!\n");  
    }
    
    else  
    {
        printf("False: Invalid initial Sudoku matrix!\n");
        printf("No solution!\n");
    }
}