minHeap and maxHeap

heap.cpp

#include <iostream>
#include <queue>
#include <iomanip>

using std::cin, std::cout;
using Left = std::priority_queue<double>;
using Right = std::priority_queue<double, std::vector<double>, std::greater<double>>;

int main() {
    double value = 0;
    Left l;// MaxHeap
    Right r;// MinHeap
    int size;
    cin >> size;
    while (cin >> value) {
        // first insert
        if (l.empty()) {
            l.push(value);
        } else if (value > l.top()) {
            r.push(value);
        } else l.push(value);
        // move top value from left to right
        // or from right to left
        if (l.size() > r.size() + 1) {
            r.push(l.top());
            l.pop();
        } else if (r.size() > l.size()) {
            l.push(r.top());
            r.pop();
        }
        // median
        if (l.size() > r.size()) {
            cout << std::fixed
                 << std::setprecision(1)
                 << l.top()
                 << '\n';
        } else cout << std::fixed
                    << std::setprecision(1)
                    << (l.top() + r.top()) / 2.
                    << '\n';
    }
    return 0;
}