419.cpp

// onepass.cpp
class Solution {
public:
  int countBattleships(vector<vector<char>> &board) {
    int count = 0, row = board.size();
    if (row == 0)
      return 0;
    int col = board[0].size();
    for (int i = 0; i < row; ++i)
      for (int j = 0; j < col; ++j)
        count += board[i][j] == 'X' && (j == 0 || board[i][j - 1] != 'X') &&
                 (i == 0 || board[i - 1][j] != 'X');
    return count;
  }
};