# LeetCode - 0036. Valid Sudoku
### 題目網址：https://leetcode.com/problems/valid-sudoku/
###### tags: `LeetCode` `Medium` `陣列`

/*
    -LeetCode format-
    Problem: 36. Valid Sudoku
    Difficulty: Medium
    
    by Inversionpeter
*/



class Solution {
public:
    bool isValidSudoku(vector<vector<char>>& board) {
        static int row, column, counts, i, j, k, l;
        for (i = 0; i < 9; ++i) {
            for (j = 0, counts = 0; j < 9; ++j) 
                if (board[i][j] != '.') {
                    if (counts & (1 << (board[i][j] - '0')))
                        return false;
                    counts |= (1 << (board[i][j] - '0'));
                }
            for (j = 0, counts = 0; j < 9; ++j) 
                if (board[j][i] != '.') {
                    if (counts & (1 << (board[j][i] - '0')))
                        return false;
                    counts |= (1 << (board[j][i] - '0'));
                }
        }
        for (i = 0; i < 3; ++i) {
            row = i * 3;
            for (j = 0; j < 3; ++j) {
                column = j * 3;
                for (k = 0, counts = 0; k < 3; ++k)
                    for (l = 0; l < 3; ++l)
                        if (board[row + k][column + l] != '.') {
                            if (counts & (1 << (board[row + k][column + l] - '0')))
                                return false;
                            counts |= (1 << (board[row + k][column + l] - '0'));
                        }
            }
        }
        return true;
    }
};