[leetcode 37] Sudoku Solver

最新推荐文章于 2025-12-27 20:58:23 发布

原创最新推荐文章于 2025-12-27 20:58:23 发布 · 256 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#leetcode #backtracking #dfs

[LeetCode 刷题] 专栏收录该内容

158 篇文章

订阅专栏

本文介绍了一个使用回溯算法解决数独问题的C++程序。该程序通过递归地尝试填入数字并验证其是否符合数独规则来寻找唯一解。

Write a program to solve a Sudoku puzzle by filling the empty cells.

Empty cells are indicated by the character '.'.

You may assume that there will be only one unique solution.

A sudoku puzzle...

...and its solution numbers marked in red.

class Solution {
public:
    bool solveSudoku(vector<vector<char> > &board) {
        for (int i = 0; i < 9; i++) {
            for (int j = 0; j < 9; j++) {
                if (board[i][j] == '.') {
                    for (int k = 0; k < 9; k++) {
                        board[i][j] = '1' + k;
                        if (isVaild(board, i, j) && solveSudoku(board)) {
                            return true;
                        }
                        board[i][j] = '.';
                    }
                    return false;
                }
            }
        }
        return true;
        
    }
    bool isVaild(vector<vector<char> > &board, int x, int y) {
        for (int i = 0; i < 9; i++) {
            if (i != y && board[x][i] == board[x][y]) {
                return false;
            }
        }
        for (int i = 0; i < 9; i++) {
            if (i != x && board[i][y] == board[x][y]) {
                return false;
            }
        }
        for (int i = 3*(x/3); i < 3*(x/3+1); i++) {
            for (int j = 3*(y/3); j < 3*(y/3+1); j++) {
                if ((i != x || j != y) && board[i][j] == board[x][y]) {
                    return false;
                }
            }
        }
        return true;
    }
};