https://leetcode.com/problems/valid-sudoku/

												  <- high -- low ->
	  +------------------- wow(row(i):0,col(j):0) 0 -> [ 0010, 0010 ]
	  |                                           1 -> [ 0000, 0000 ]
	  |                                           2 -> [ 0000, 0000 ]
	  |
	  |   +--------------- wow(row(i):0,col(j):1) 0 -> [ 0010 | 1 = 0011, 0010 ]
	  |   |                                       1 -> [ 0000, 0000 | 1 = 0001 ]
	  |   |                                       2 -> [ 0000, 0000 ]
	  |   |
	  |   |   +----------- wow(row(i):0,col(j):2) 0 -> [ 0011 | 3 = 0100, 0010 ]
	  |   |   |                                   1 -> [ 0000, 0001 ]
	  |   |   |                                   2 -> [ 0000, 0000 | 3 = 0100 ]
	+---+---+---+
	| 2 | 1 | 3 |
	+---+---+---+
----| 3 | 2 | 1 |
|   +---+---+---+
|   | 1 | 3 | 2 |
|   +---+---+---+     |- wow(row(i):1,col(j):0) 0 -> [0010 | 3 = 0110, 0010]
+---------------------+                         1 -> [0000, 0001 | 3 = 0101]                                                 2 -> [0000, 0100]

class Solution {
public:
	bool isValidSudoku(vector<vector<char>>& board) {
		vector<int> wow(9,0);
		int mux1;
		int mux2;
		int mux3;
		int box_index;

		for(int i=0;i<9;i++){
			for(int j=0;j<9;j++){
				if(board[i][j] == '.'){
					continue;
				}
				mux1 = 0x01 << (board[i][j] - '1');
				mux2 = 0x01 << 9 << (board[i][j] - '1');
				mux3 = 0x01 << 9 << 9 << (board[i][j] - '1');
				box_index = (i/3) * 3 + j/3;
				if((wow[i]&mux1) != mux1 && (wow[j]&mux2) != mux2 && (wow[box_index]&mux3) != mux3){
					wow[i] = wow[i]|mux1;
					wow[j] = wow[j]|mux2;
					wow[box_index] = wow[box_index]|mux3;
				}
				else{
					return false;
				}
			}
		}
		return true;
	}
};