I could use a review of my sudoku validation

Question

I'm looking for alternative ways to do it and in general parts that don't look write on this code.

using System.Collections.Generic;

namespace Algorithms 
{ 
    public class SudokuPuzzleValidator 
    { 
        readonly int[,] _board;

        public SudokuPuzzleValidator() 
        { 
            _board = new int[9,9]; 
        }

        public SudokuPuzzleValidator(int[,] board) 
        { 
            _board = board; 
        }

        public bool Validate() 
        { 
            const int integersInGame = 9; 
            var rowSet = new HashSet<int>[integersInGame]; 
            InitializeSet(integersInGame, rowSet); 
            var columnSet = new HashSet<int>[integersInGame]; 
            InitializeSet(integersInGame, columnSet); 
            var subGridSet = new HashSet<int>[integersInGame]; 
            InitializeSet(integersInGame, subGridSet);

            for (var row = 0; row < integersInGame; row++) 
            { 
                for (var column = 0; column < integersInGame; column++) 
                { 
                    var cval = _board[row, column]; 
                    if (rowSet[row].Contains(cval)) 
                    { 
                        return false; 
                    } 
                    rowSet[row].Add(cval); 
                    if (columnSet[column].Contains(cval)) 
                    { 
                        return false; 
                    } 
                    columnSet[column].Add(cval); 
                    var subGridNumber = FigureOutSubGrid(row, column); 
                    if (subGridSet[subGridNumber].Contains(cval)) 
                    { 
                        return false; 
                    } 
                    subGridSet[subGridNumber].Add(cval); 
                } 
            } 
            return true; 
        }

        private static void InitializeSet(int integersInGame, HashSet<int>[] rowSet) 
        { 
            for (var i = 0; i < integersInGame; i++) 
            { 
                rowSet[i] = new HashSet<int>(); 
            } 
        }

        private static int FigureOutSubGrid(int row, int column) 
        { 
            return column/3 + row/3*3; 
        } 
    } 
}

Link to my post: http://alfredoalvarez.com/blog/?p=372

Answer 1

This looks way overcomplicated. There are a lot of solutions on the web, for example: http://stackoverflow.com/questions/723213/sudoku-algorithm-in-c-sharp

Regarding your code:

• You have hard-coded numbers everywhere
• Second ctor accepts arbitrary array and does not check parameter for validity. It can be null or of any size different from 9