LeetCode – Refresh – Valid Sudoku

 1 class Solution {
 2 public:
 3     bool isValid(vector<bool> &rec, int value) {
 4         if (value < 0) return true;
 5         if (rec[value]) return false;
 6         rec[value] = true;
 7         return true;
 8     }
 9     bool isValidSudoku(vector<vector<char> > &board) {
10         if (board.size() != 9 || board[0].size() != 9) return false;
11         for (int i = 0; i < 9; i++) {
12             vector<bool> row(10, false), column(10, false), sub(10, false);
13             for (int j = 0; j < 9; j++) {
14                 if (!isValid(row, board[i][j] - ‘0‘) ||
15                     !isValid(column, board[j][i] - ‘0‘) ||
16                     !isValid(sub, board[(i/3)*3 + j/3][(i%3)*3 + j%3] - ‘0‘)) {
17                         return false;
18                 }
19             }
20         }
21         return true;
22     }
23 };