yuanshen/2.c

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

void printMatrix(char matrix[9][9])
{
    for (int i = 0; i < 9; i++)
    {
        for (int j = 0; j < 9; j++)
        {
            printf("%c ", matrix[i][j]);
        }
        printf("\n");
    }
}

void generateRow(char row[9], int nums[9])
{
    // Fill the row with '0'
    for (int i = 0; i < 9; i++)
    {
        row[i] = '0';
    }

    // Place three unique numbers from the provided nums array into random positions
    for (int i = 0; i < 3; i++)
    {
        int pos;
        do
        {
            pos = rand() % 9;
        } while (row[pos] != '0'); // Find an empty position
        row[pos] = nums[i] + '0'; // Store as char
    }
}

void generateUniqueRows(char matrix[9][9], int startRow) {
    int nums[9] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    // Shuffle numbers
    for (int i = 8; i > 0; i--) {
        int j = rand() % (i + 1);
        int temp = nums[i];
        nums[i] = nums[j];
        nums[j] = temp;
    }

    // Fill 3 rows with 3 unique numbers each
    for (int i = 0; i < 3; i++) {
        generateRow(matrix[startRow + i], nums + i * 3);
    }
}

int main() {
    srand(time(NULL)); // Set random seed

    char matrix[9][9];

    // Generate the first three rows
    generateUniqueRows(matrix, 0);

    // Generate the next three rows
    generateUniqueRows(matrix, 3);

    // Generate the last three rows
    generateUniqueRows(matrix, 6);

    // Print the matrix
    printMatrix(matrix);

    return 0;
}