drdg/program2.c

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

void printMatrix(int matrix[9][9]) {
    for (int i = 0; i < 9; i++) {
        if (i == 0 || i == 3 || i == 6) {
            printf("|-----------------------|\n");
        }
        for (int j = 0; j < 9; j++) {
            if (j == 0 || j == 3 || j == 6) {
                printf("| ");
            }
            if (matrix[i][j] == 0)
            {
                printf(". ");
            }
            else {
                printf("%d ", matrix[i][j]);
            }
        }
        printf("|\n");
    }
    printf("|-----------------------|\n");
}

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

int isInGroup(int matrix[9][9], int startRow, int startCol, int num) {
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            if (matrix[startRow + i][startCol + j] == num) {
                return 1;
            }
        }
    }
    return 0;
}

int main() {
    srand(time(NULL));
    int matrix[9][9] = { 0 };
    int numbers[9] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

    for (int group = 0; group < 3; group++) {
        int usedNumbers[9] = { 0 };
        for (int i = 0; i < 9; i++) {
            usedNumbers[i] = numbers[i];
        }

        for (int i = 0; i < 9; i++) {
            int idx = rand() % (9 - i);
            int temp = usedNumbers[idx];
            usedNumbers[idx] = usedNumbers[8 - i];
            usedNumbers[8 - i] = temp;
        }

        for (int row = 0; row < 3; row++) {
            int count = 0;
            while (count < 3) {
                int num;
                do {
                    int idx = rand() % 9;
                    num = usedNumbers[idx];
                } while (num == 0 || isInRow(matrix, group * 3 + row, num) || isInGroup(matrix, group * 3, 0, num));

                int pos;
                do {
                    pos = rand() % 9;
                } while (matrix[group * 3 + row][pos] != 0);

                matrix[group * 3 + row][pos] = num;
                count++;
            }
        }
    }

    for (int row = 0; row < 9; row++) {
        int uniqueNumbers[9] = { 0 };
        int uniqueCount = 0;
        for (int i = 0; i < 9; i++) {
            if (matrix[row][i] != 0 && !uniqueNumbers[matrix[row][i] - 1]) {
                uniqueNumbers[matrix[row][i] - 1] = 1;
                uniqueCount++;
            }
        }
        if (uniqueCount > 3) {
            while (uniqueCount > 3) {
                int idx = rand() % 9;
                if (matrix[row][idx] != 0 && uniqueNumbers[matrix[row][idx] - 1]) {
                    matrix[row][idx] = 0;
                    uniqueCount--;
                }
            }
        }
        else if (uniqueCount < 3) {
            while (uniqueCount < 3) {
                int num;
                do {
                    num = rand() % 9 + 1;
                } while (uniqueNumbers[num - 1]);
                int idx;
                do {
                    idx = rand() % 9;
                } while (matrix[row][idx] != 0);
                matrix[row][idx] = num;
                uniqueNumbers[num - 1] = 1;
                uniqueCount++;
            }
        }
    }

    printMatrix(matrix);

    return 0;
}