text: class Solution {
  public:
      bool isValidSudoku(vector<vector<char>>& board) {
  
      }
  
      bool isValidRow(vector<vector<char>>& board)
      {
          map<char, int>rowcount;
  
          for (int i = 0; i < 9; ++i)
          {
              rowcount.clear();
              for (int j = 0; j < 9; ++j)
              {
                  if (rowcount.find(board[i][j]) == rowcount.end())
                  {
                      rowcount[board[i][j]]=1;
                      continue;
                  }
                  else
                  {
                      return false;
                  }
              }
          }
  
          return true;               
      }
      
      bool isValidRank(vector<vector<char>>& board)
      {
          map<char, int>rankcount;
  
          for (int i = 0; i < 9; ++i)
          {
              rankcount.clear();
              for (int j = 0; j <9; ++j)
              {
                  if (rankcount.find(board[j][i]) == rankcount.end())
                  {
                      rankcount[board[j][i]]=1;
                      continue;
                  }
                  else
                  {
                      return false;
                  }
              }
          }
  
          return true;               
      }
      
      bool isValidBox(vector<vector<char>>& board)
      {
          map<char, int>boxcount;
      }
  };