In C++, priority_queue implements heap. Below are some examples of creating priority queue of pair type.
Max Priority queue (Or Max heap) ordered by first element
// C++ program to create a priority queue of pairs. // By default a max heap is created ordered // by first element of pair. #include <bits/stdc++.h> using namespace std;
// Driver program to test methods of graph class int main()
{ // By default a max heap is created ordered
// by first element of pair.
priority_queue<pair< int , int > > pq;
pq.push(make_pair(10, 200));
pq.push(make_pair(20, 100));
pq.push(make_pair(15, 400));
pair< int , int > top = pq.top();
cout << top.first << " " << top.second;
return 0;
} |
Output :
20 100
Min Priority queue (Or Min heap) ordered by first element
// C++ program to create a priority queue of pairs. // We can create a min heap by passing adding two // parameters, vector and greater(). #include <bits/stdc++.h> using namespace std;
typedef pair< int , int > pi;
// Driver program to test methods of graph class int main()
{ // By default a min heap is created ordered
// by first element of pair.
priority_queue<pi, vector<pi>, greater<pi> > pq;
pq.push(make_pair(10, 200));
pq.push(make_pair(20, 100));
pq.push(make_pair(15, 400));
pair< int , int > top = pq.top();
cout << top.first << " " << top.second;
return 0;
} |
Output :
10 200
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