leetcode36

public class Solution
    {
        public bool IsValidSudoku(char[,] board)
        {
            for (int i = 0; i < 9; i++)
            {
                var dic = new Dictionary<char, int>();
                for (int j = 0; j < 9; j++)
                {
                    var num = board[i, j];
                    if (num == '.')
                    {
                        continue;
                    }
                    if (dic.ContainsKey(num))
                    {
                        return false;
                    }
                    else
                    {
                        dic.Add(num, 1);
                    }
                }
                dic.Clear();
            }

            for (int j = 0; j < 9; j++)
            {
                var dic = new Dictionary<char, int>();
                for (int i = 0; i < 9; i++)
                {
                    var num = board[i, j];
                    if (num == '.')
                    {
                        continue;
                    }
                    if (dic.ContainsKey(num))
                    {
                        return false;
                    }
                    else
                    {
                        dic.Add(num, 1);
                    }
                }
                dic.Clear();
            }

            for (int a = 0; a < 3; a++)
            {
                for (int b = 0; b < 3; b++)
                {                    
                    var dic = new Dictionary<char, int>();
                    for (int i = 3 * a; i < 3 * (a + 1); i++)
                    {
                        for (int j = 3 * b; j < 3 * (b + 1); j++)
                        {
                            //Console.Write(i + "," + j + " ");
                            var num = board[i, j];
                            if (num == '.')
                            {
                                continue;
                            }
                            if (dic.ContainsKey(num))
                            {
                                return false;
                            }
                            else
                            {
                                dic.Add(num, 1);
                            }
                        }
                    }
                    dic.Clear();
                    //Console.WriteLine();
                }
            }
            return true;
        }
    }