leetCode Sudoku Solver-优快云博客

本文链接：https://blog.youkuaiyun.com/CSLDBLYDX/article/details/41931503

本文介绍了一种使用回溯算法解决数独问题的方法。通过验证每个空格填入数字的可能性来寻找唯一解，并实现了相应的C++程序代码。

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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 avalid(vector<vector<char> > &board,int count, int num)
	{
		char chr = '0' + num;
		int row = count / 9;
		int col = count % 9;
		int b_r = row / 3 * 3;
		int b_c = col / 3 * 3;
		for(int i = 0; i < 3; i++)
			for(int j = 0; j < 3; j++)
			{
				if(board[b_r + i][b_c + j] == chr)return false;
			}

		for(int i = 0; i < 9; i++)
			if(board[row][i] == chr)return false;
		for(int i = 0; i < 9; i++)
			if(board[i][col] == chr)return false;

		return true;
		
	}

    bool solve(vector<vector<char> > &board, int count)
    {
        if(count == 81)return true;

        
		int row = count / 9;
		int col = count % 9;
		int b_r = row / 3 * 3;
		int b_c = col / 3 * 3;

		if(board[row][col] != '.')return solve(board, count + 1);
		

		for(int i = 1; i <= 9; i++)
		{
			if(avalid(board, count, i))
			{
				board[row][col] = '0' + i;
				if(solve(board, count))return true;
				board[row][col] = '.';
			}
		}

		return false;
	
    }

    void solveSudoku(vector<vector<char> > &board)
    {
        solve(board, 0);
    }

};