Method iter

code/other/dpll.cpp:9–11

  int var() { return ++n; }
  void clause(vi vars) {
    set<int> seen; iter(it,vars) {
      if (seen.find(IDX(*it)^1) != seen.end()) return;
      seen.insert(IDX(*it)); }
    head.push_back(cl.size());
    iter(it,seen) cl.push_back(*it);
    tail.push_back((int)cl.size() - 2); }