http://www.weibo.com/1915548291/ziWv47wlW

domain_cover.cc

#include <algorithm>
#include <fstream>
#include <iostream>
#include <string>
#include <vector>

using namespace std;

bool covered(const vector<string>& filters, const string& line)
{
  typedef vector<string>::const_iterator Iterator;
  Iterator filter = lower_bound(filters.begin(), filters.end(), line);
  if (filter != filters.end() && *filter == line)
    return true;
  if (filter != filters.begin())
  {
    --filter;
    if (line.size() >= filter->size()
        && equal(filter->begin(), filter->end(), line.begin()))
      return true;
  }
  return false;
}

int main(int argc, char* argv[])
{
  if (argc == 3)
  {
    vector<string> filters;
    {
      ifstream in2(argv[2]);
      string filter;
      while (getline(in2, filter))
      {
        reverse(filter.begin(), filter.end());
        if (filter[filter.size()-1] != '.')
          filter.push_back('.');

        filters.push_back(filter);
      }
    }
    sort(filters.begin(), filters.end());

    {
      ifstream in1(argv[1]);
      string line;
      while (getline(in1, line))
      {
        reverse(line.begin(), line.end());
        if (line[line.size()-1] != '.')
          line.push_back('.');
        
        if (!covered(filters, line))
        {
          cout << "remain " << line << '\n';
        }
      }
    }
  }
}