#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
int main(){
int n, i, elems_to_pop;
double med;
std::vector<int> v;
n = i = 0;
while(std::cin >> i){
v.push_back(i);
n++;
}
std::make_heap(v.begin(), v.end());
if(n & 0x1){ //n - нечетное
elems_to_pop = (n - 1) / 2; //Сколько элементов снять с кучи, чтобы добраться до медианы
while(elems_to_pop){
std::pop_heap(v.begin(), v.end());
v.pop_back();
med = v.front();
elems_to_pop--;
}
std::cout << med; //Медиана в случае нечетного n
}else{ //n - четное
elems_to_pop = (n / 2) - 1; //Сколько элементов снять с кучи перед расчетом медианы
while(elems_to_pop){
std::pop_heap(v.begin(), v.end());
v.pop_back();
med = v.front();
elems_to_pop--;
}
std::cout << ((med + v.front()) / 2.0); //Медиана в случае четного n
}
}
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