#include <stdio.h>


int checkRows(int matrix[9][9]) {
    for (int i = 0; i < 9; i++) {
        int count[10] = {0};
        for (int j = 0; j < 9; j++) {
            if (matrix[i][j] >= 1 && matrix[i][j] <= 9) {
                if (count[matrix[i][j]] == 1) {
                    return 0;
                }
                count[matrix[i][j]]++;
            }
        }
    }
    return 1;
}


int checkColumns(int matrix[9][9]) {
    for (int j = 0; j < 9; j++) {
        int count[10] = {0};
        for (int i = 0; i < 9; i++) {
            if (matrix[i][j] >= 1 && matrix[i][j] <= 9) {
                if (count[matrix[i][j]] == 1) {
                    return 0;
                }
                count[matrix[i][j]]++;
            }
        }
    }
    return 1;
}


int checkSubMatrices(int matrix[9][9]) {
    for (int blockRow = 0; blockRow < 3; blockRow++) {
        for (int blockCol = 0; blockCol < 3; blockCol++) {
            int count[10] = {0};
            for (int i = blockRow * 3; i < blockRow * 3 + 3; i++) {
                for (int j = blockCol * 3; j < blockCol * 3 + 3; j++) {
                    if (matrix[i][j] >= 1 && matrix[i][j] <= 9) {
                        if (count[matrix[i][j]] == 1) {
                            return 0;
                        }
                        count[matrix[i][j]]++;
                    }
                }
            }
        }
    }
    return 1;
}


void printMatrix(int matrix[9][9]) {
	printf("|--------------------|\n|");
    for (int i = 0; i < 9; i++) {
        for (int j = 0; j < 9; j++) {
            printf("%d ", matrix[i][j]);
            if((i+1)%1==0&&(j+1)%3==0) printf("|");
 if((i+1)%3==0&&(j+1)%9==0) printf("\n|--------------------|");
 if((j+1)==9&&i!=8) printf("\n|");
        }
        
    }
}


int findUnassignedLocation(int matrix[9][9], int *row, int *col) {
    for (*row = 0; *row < 9; (*row)++) {
        for (*col = 0; *col < 9; (*col)++) {
            if (matrix[*row][*col] == 0) {
                return 1;
            }
        }
    }
    return 0;
}


int isSafe(int matrix[9][9], int row, int col, int num) {
   
    for (int i = 0; i < 9; i++) {
        if (matrix[row][i] == num) {
            return 0;
        }
    }

    
    for (int i = 0; i < 9; i++) {
        if (matrix[i][col] == num) {
            return 0;
        }
    }

 
    int startRow = row - row % 3;
    int startCol = col - col % 3;
    for (int i = startRow; i < startRow + 3; i++) {
        for (int j = startCol; j < startCol + 3; j++) {
            if (matrix[i][j] == num) {
                return 0;
            }
        }
    }

    return 1;
}


int solveSudoku(int matrix[9][9]) {
    int row, col;
    if (!findUnassignedLocation(matrix, &row, &col)) {
        return 1;
    }

    for (int num = 1; num <= 9; num++) {
        if (isSafe(matrix, row, col, num)) {
            matrix[row][col] = num;
            if (solveSudoku(matrix)) {
                return 1;
            }
            matrix[row][col] = 0;
        }
    }

    return 0;
}

int main() {
    int matrix[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("The original Sudoku matrix: \n");
    printMatrix(matrix);

    
    if (checkRows(matrix) && checkColumns(matrix) && checkSubMatrices(matrix)) {
        printf("True:Valid initial Sudoku matrix!\n");

      
        if (solveSudoku(matrix)) {
            printf("The solution of Sudoku matrix:\n");
            printMatrix(matrix);
        } else {
            printf("No solution!\n");
        }
    } else {
        printf("False:Invalid initial Sudoku matrix!\n");

       
        for (int i = 0; i < 9; i++) {
            int count[10] = {0};
            for (int j = 0; j < 9; j++) {
                if (matrix[i][j] >= 1 && matrix[i][j] <= 9) {
                    if (count[matrix[i][j]] == 1) {
                        printf("The number %d in the row %d has been used!\n", matrix[i][j], i + 1);
                        break;
                    }
                    count[matrix[i][j]]++;
                }
            }
        }

     
        for (int j = 0; j < 9; j++) {
            int count[10] = {0};
            for (int i = 0; i < 9; i++) {
                if (matrix[i][j] >= 1 && matrix[i][j] <= 9) {
                    if (count[matrix[i][j]] == 1) {
                        printf("The number %d in the col %d has been used!\n", matrix[i][j], j + 1);
                        break;
                    }
                    count[matrix[i][j]]++;
                }
            }
        }

       
        for (int blockRow = 0; blockRow < 3; blockRow++) {
            for (int blockCol = 0; blockCol < 3; blockCol++) {
                int count[10] = {0};
                for (int i = blockRow * 3; i < blockRow * 3 + 3; i++) {
                    for (int j = blockCol * 3; j < blockCol * 3 + 3; j++) {
                        if (matrix[i][j] >= 1 && matrix[i][j] <= 9) {
                            if (count[matrix[i][j]] == 1) {
                                printf("The number %d in the block %d has been used!\n", matrix[i][j], blockRow * 3 + blockCol + 1);
                                break;
                            }
                            count[matrix[i][j]]++;
                        }
                    }
                }
            }
        }

        printf("No solution!\n");
    }

    return 0;
}