36 Valid Sudoku

public static boolean isValidSudoku(char[][] board) {

Set<Character> set = new HashSet<Character>();

for (int i = 0; i < 9; i++) {
set.clear();
for (int j = 0; j < 9; j++) {
if (board[i][j] != '.') {
if (set.add(board[i][j]))
continue;
else
return false;
}
}
}

for (int i = 0; i < 9; i++) {
set.clear();
for (int j = 0; j < 9; j++) {
if (board[j][i] != '.') {
if (set.add(board[j][i]))
continue;
else
return false;
}
}
}

for (int i = 0; i < 9; i+=3) {
for (int j = 0; j < 9; j+=3) {
set.clear();
for (int m = 0; m < 3; m++) {
for (int n = 0; n < 3; n++) {
if (board[i+m][j+n] != '.') {
if (set.add(board[i+m][j+n]))
continue;
else
return false;
}
}
}
}
}
return true;
}