leetCode 36. Valid Sudoku(數獨) 雜湊

weixin_33858249發表於2017-11-13
LeetCode

36. Valid Sudoku(合法數獨)

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 '.'.

250px-Sudoku-by-L2G-20050714.svg.png

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.

關於數獨的簡介：

There are just 3 rules to Sudoku.

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

horizontal.jpg

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

vertical.jpg

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

square.jpg

題目大意：

判斷一個給定的二維陣列是否是一個合法的數獨矩陣。

思路:

採用set這一容器，來進行去重。

1.判斷每一行是否合法。

2.判斷每一列是否合法。

3.判斷每一個九宮格是否合法。

程式碼如下：

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class Solution {
public:
    bool isValidSudoku(vector<vector<char>>& board) 
    {
        set<char> mySet;
        //1.判斷每一行是否合法
        for (int row = 0; row < 9; row++)
        {
            //cout<<"檢測行:"<<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.判斷每一列是否合法
        for (int row = 0; row < 9; row++)
        {
            //cout<<"檢測列:"<<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.判斷每一個九宮格是否合法
        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;
    }
};

本文轉自313119992 51CTO部落格，原文連結:http://blog.51cto.com/qiaopeng688/1837537

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