leetcode-哈希表-36.有效的数独

/** C++
 * Valid Sudoku
 * 有效的数独
*/

class Solution 
{
public:
    bool isValidSudoku(vector<vector<char> > &board) 
	{
        const int cnt = 9;
        bool row_mask[cnt][cnt] = {false};
        bool col_mask[cnt][cnt] = {false};
        bool area_mask[cnt][cnt] = {false};
        //check each rows and cols
        for(int r=0; r<board.size(); r++)
		{
            for (int c=0; c<board[r].size(); c++)
			{
                if (!isdigit(board[r][c])) continue;
                int idx =  board[r][c] - '0' - 1;
                
                //check the rows
                if (row_mask[r][idx] == true)
				{
                    return false;
                }
                row_mask[r][idx] = true;
                
                //check the cols
                if (col_mask[c][idx] == true) 
				{
                    return false;
                }
                col_mask[c][idx] = true;
                
                //check the areas
                int area = (r/3) * 3 + (c/3);
                if (area_mask[area][idx] == true) 
				{
                    return false;
                }
                area_mask[area][idx] = true;
            }
        }
        
        return true;
    }
};

/** Pyhton
 * Valid Sudoku
 * 有效的数独
*/

class Solution(object):
    def isValidSudoku(self, board):
        """
        :type board: List[List[str]]
        :rtype: bool
        """
        cacheCol = [[0] * 9 for _ in xrange(0, 10)]
        cacheRow = [[0] * 9 for _ in xrange(0, 10)]
        cacheBox = [[0] * 9 for _ in xrange(0, 10)]
        
        for i in xrange(0, 9):
            for j in xrange(0, 9):
                ib = (i/3)*3 + j/3
                if board[i][j] == ".":
                    continue
                num = int(board[i][j]) - 1
                if cacheRow[i][num] != 0 or cacheCol[j][num] != 0 or cacheBox[ib][num] != 0:
                    return False
                cacheRow[i][num] = 1
                cacheCol[j][num] = 1
                cacheBox[ib][num] = 1
        return True