STL — Standard Template Library

Cozi (queue)

queue<T> implementează FIFO (First In, First Out) — primul adăugat e primul scos.

#include <queue>
using namespace std;

queue<int> q;
q.push(1);
q.push(2);
q.push(3);

cout << q.front() << endl; // 1 (primul adăugat)
cout << q.back()  << endl; // 3 (ultimul adăugat)
q.pop();                    // elimină 1
cout << q.front() << endl; // 2

Priority queue (coadă cu priorități)

priority_queue<int> pq;  // max-heap implicit
pq.push(3); pq.push(1); pq.push(4); pq.push(2);
while (!pq.empty()) {
  cout << pq.top() << " ";  // 4 3 2 1
  pq.pop();
}

priority_queue implicit e un max-heap (elementul maxim e la top). Pentru min-heap: priority_queue<int, vector<int>, greater<int>>.