[LeetCode] Sudoku Solver

最新推荐文章于 2018-07-17 09:15:56 发布

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本文介绍了一个用于填充空格以解决数独谜题的编程算法。该算法通过验证每一行、每一列和每个九宫格内的唯一数字来确保解决方案的正确性。它从空格开始遍历，尝试填入1到9之间的数字，并递归地验证每个可能的选择，直到找到唯一的解决方案。

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 isVaild(vector<vector<char> > &board,int a,int b){
        for(int row = 0;row < 9;row ++){
            if(row != a && board[a][b] == board[row][b])
                return false;
        }
        for(int column = 0;column < 9;column ++){
            if(column != b && board[a][b] == board[a][column])
                return false;
        }
        int x = (a/3)*3 ,y = (b/3)*3;
        for(int i = 0;i < 3;i ++){
            for(int j = 0;j < 3;j ++){
                if(x + i!= a && y + j!= b && board[a][b] == board[x + i][y + j])
                    return false;
            }
        }
        return true;
    }
    
    bool generate(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 = 1;k <= 9;k ++){
                        board[i][j] = k + '0';
                        if(isVaild(board, i, j) && generate(board))
                            return true;
                        board[i][j] = '.';
                    }
                    return false;
                }
            }
        }
        return true;
    }
    void solveSudoku(vector<vector<char> > &board) {
        generate(board);
    }
};