[lintcode easy]Valid Sudoku

class Solution {
    /**
      * @param board: the board
        @return: wether the Sudoku is valid
      */
    public boolean isValidSudoku(char[][] board) {
        int m=board.length;
        int n=board[0].length;   
        
        if(board.length!=9 || board[0].length!=9) return false;
        
        boolean isRow=isValidRow(board);
        boolean isCol=isValidCol(board);
        boolean isNine=isValidNine(board);
        
        if(isRow && isCol && isNine)
        {
            return true;
        }
        
        else
        return false;
        
    }
    
    public boolean isValidRow(char[][] board)
    {
        
        for(int i=0;i<9;i++)
        {
            boolean[] isValid=new boolean[10];
            int val=0;
            for(int j=0;j<9;j++)
            {
              if(board[i][j]==‘.‘)
              {
                  continue;
              }
              else
              {
                 val=board[i][j]-‘0‘;
              }
              
              if(isValid[val])
              {
                return false;
              }
              else
              {
                isValid[val]=true;
              }
            }

        }
        return true;
    }
    
        
    public boolean isValidCol(char[][] board)
    {
        
        for(int i=0;i<9;i++)
        {
            boolean[] isValid=new boolean[10];
            int val=0;
            for(int j=0;j<9;j++)
            {
              if(board[j][i]==‘.‘)
              {
                    continue;
              }
              else
              {
              val=board[j][i]-‘0‘;
              }
              if(isValid[val])
              {
                return false;
              }
              else
              {
                isValid[val]=true;
              }
            }
        }
        return true;
    }
    
    public boolean isValidNine(char[][] board)
    {
        for(int i=0;i<9;i+=3)
        {
            for(int j=0;j<9;j+=3)
            {
                boolean[] isValid=new boolean[10];
                int val=0;
                for(int a=0;a<3;a++)
                {
                    for(int b=0;b<3;b++)
                    {
                    
                        if(board[i+a][j+b]==‘.‘)
                        { 
                            continue;
                        }
                        else
                        {
                            val=board[i+a][j+b]-‘0‘;
                        }
            
                        if(isValid[val])
                       {
                           return false;
                        }
                        else
                       {
                           isValid[val]=true;
                       }
                    }
                }
            }
        }
        return true;
    }
};