CPP

how to use comparator funtion in priority queue in c++

// suppose you want to apply comparator on pair <int, string>
// declaration of priority queue
priority_queue<pair<int, string>, vector<pair<int, string>>, myComp> pq;
// here myComp is comparator
struct myComp {
  bool operator()(
    pair<int, string>& a,
    pair<int, string>& b)
  {
    return a.first > b.first;
    // can write more code if required. depends upon requirement.
  }
};
// another way 
 auto compare = [](int lhs, int rhs){
  return lhs < rhs;
};

priority_queue<int, vector<int>, decltype(compare) > pq(compare);

comparator for priority queue c++

class Foo
{

};

class Compare
{
public:
    bool operator() (Foo, Foo)
    {
        return true;
    }
};

int main()
{
    std::priority_queue<Foo, std::vector<Foo>, Compare> pq;
    return 0;
}

comparator priority queue c++

struct CompareHeight {
    bool operator()(Person const& p1, Person const& p2)
    {
        // return "true" if "p1" is ordered
        // before "p2", for example:
        return p1.height < p2.height;
    }
};