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leetCode 36. Valid Sudoku(数独) 哈希

更新时间:2022-10-03 13:48:15

36. Valid Sudoku(合法数独)

Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules.

The Sudoku board could be partially filled, where empty cells are filled with the character '.'.

leetCode 36. Valid Sudoku(数独) 哈希

A partially filled sudoku which is valid.


Note:
A valid Sudoku board (partially filled) is not necessarily solvable. Only the filled cells need to be validated.

关于数独的简介:

There are just 3 rules to Sudoku.

1.Each row must have the numbers 1-9 occuring just once.

leetCode 36. Valid Sudoku(数独) 哈希

2.Each column must have the numbers 1-9 occuring just once.

leetCode 36. Valid Sudoku(数独) 哈希

3.And the numbers 1-9 must occur just once in each of the 9 sub-boxes of the grid.

leetCode 36. Valid Sudoku(数独) 哈希

题目大意:

判断一个给定的二维数组是否是一个合法的数独矩阵。

思路:

采用set这一容器,来进行去重。

1.判断每一行是否合法。

2.判断每一列是否合法。

3.判断每一个九宫格是否合法。

代码如下:

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class Solution {
public:
    bool isValidSudoku(vector<vector<char>>& board) 
    {
        set<char> mySet;
        //1.判断每一行是否合法
        for (int row = 0; row < 9; row++)
        {
            //cout<<"检测行:"<<row<<endl;
            for (int column = 0; column < 9; column++)
            {
                if (board[row][column] == '.')
                {
                    continue;
                }
                if (mySet.find(board[row][column]) == mySet.end())
                {
                    mySet.insert(board[row][column]);
                }
                else
                {
                    return false;
                }
            }
            mySet.clear();
        }
         
        //2.判断每一列是否合法
        for (int row = 0; row < 9; row++)
        {
            //cout<<"检测列:"<<row<<endl;
            for (int column = 0; column < 9; column++)
            {
                if (board[column][row] == '.')
                {
                    continue;
                }
                if (mySet.find(board[column][row]) == mySet.end())
                {
                    mySet.insert(board[column][row]);
                }
                else
                {
                    return false;
                }
            }
            mySet.clear();
        }
     
        //3.判断每一个九宫格是否合法
        for (int row = 0; row < 9; row += 3)
        {
            for (int column = 0; column < 9; column += 3)
            {
                for (int i = row; i < row + 3; i++)
                {
                    for (int j = column; j < column + 3; j++)
                    {
                        if (board[i][j] == '.')
                        {
                            continue;
                        }
                        if (mySet.find(board[i][j]) == mySet.end())
                        {
                            mySet.insert(board[i][j]);
                        }
                        else
                        {
                            return false;
                        }
                    }
                }
                mySet.clear();
            }
        }
        return true;
    }
};


本文转自313119992 51CTO博客,原文链接:http://blog.51cto.com/qiaopeng688/1837537