Valid Sudoku

Description

The Sudoku board could be partially filled, where empty cells are filled with the character '.'. Note: A valid Sudoku board (partially filled) is not necessarily solvable. Only the filled cells need to be validated.

Hint

Train of Thought

Each time send the coordinates to check if the board is partially valid.

Code

    public boolean isValidSudoku(char[][] board) {
        for (int i=0; i<9; i++) {
            if (!isParticallyValid(board,i,0,i,8)) return false;
            if (!isParticallyValid(board,0,i,8,i)) return false;
        }
        for (int i=0;i<3;i++){
            for(int j=0;j<3;j++){
                if (!isParticallyValid(board,i*3,j*3,i*3+2,j*3+2)) return false;
            }
        }
        return true;
    }
    private boolean isParticallyValid(char[][] board, int x1, int y1,int x2,int y2){
        Set singleSet = new HashSet();
        for (int i= x1; i<=x2; i++){
            for (int j=y1;j<=y2; j++){
                if (board[i][j]!='.') if(!singleSet.add(board[i][j])) return false;
            }
        }
        return true;
    }

Complexity