空的数独填充器C++

#include <iostream>
using namespace std;

bool isSafe(int grid[9][9], int row, int col, int num) {
    // 检查行是否安全
    for (int i = 0; i < 9; i++) {
        if (grid[row][i] == num) {
            return false;
        }
    }
    
    // 检查列是否安全
    for (int i = 0; i < 9; i++) {
        if (grid[i][col] == num) {
            return false;
        }
    }
    
    // 检查九宫格是否安全
    int startRow = row - row % 3;
    int startCol = col - col % 3;
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            if (grid[i + startRow][j + startCol] == num) {
                return false;
            }
        }
    }
    
    return true;
}

bool solveSudoku(int grid[9][9]) {
    int row, col;
    
    // 检查是否还有空格需要填充
    if (!findEmptyLocation(grid, row, col)) {
        return true; // 数独已经填充完毕
    }
    
    // 尝试填充数字
    for (int num = 1; num <= 9; num++) {
        if (isSafe(grid, row, col, num)) {
            grid[row][col] = num;
            
            // 递归地尝试填充下一个空格
            if (solveSudoku(grid)) {
                return true;
            }
            
            // 如果无法填充下一个空格，则回溯
            grid[row][col] = 0;
        }
    }
    
    return false; // 无解
}

void printGrid(int grid[9][9]) {
    for (int row = 0; row < 9; row++) {
        for (int col = 0; col < 9; col++) {
            cout << grid[row][col] << " ";
        }
        cout << endl;
    }
}

int main() {
    int grid[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}
    };
    
    if (solveSudoku(grid)) {
        cout << "解决方案：" << endl;
        printGrid(grid);
    } else {
        cout << "无解" << endl;
    }
    
    return 0;
}