36. Valid Sudoku

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 '.'.

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.

用数组标记状态，row[i][j]表示第i行的数字j有没有出现过,col 和box同理

class Solution {
public:
    bool isValidSudoku(vector<vector<char>>& board) {
        int row[10][10] = {0}, col[10][10] = {0}, box[10][10] = {0};
          for(int i = 0; i < board.size(); i++)
          {
              for(int j = 0; j < board[i].size(); j++)
              {
                  if(board[i][j] != '.')
                  {
                      int x = board[i][j] - '0' - 1;
                      int k = i/3 + j/3;
                      if(row[i][x] || col[j][x] || box[k][x])
                          return false;
                      row[i][x] = col[j][x] = box[k][x] = 1;
                  }
              }
          } 
          return true;
    }
};