int l=0, r;
for(r=0;r<n;r++) {

    if(!up.empty() && *up.begin() <= a[r]) {
        up.insert(a[r]);
    }
    else {
        low.insert(a[r]);
    }
    
    if(up.size() > low.size()) {
        low.insert(*up.begin());
        up.erase(up.begin());
    }

    if(up.size()+1 < low.size()) {
        up.insert(*low.rbegin());
        multiset<int>::iterator itr = low.end();
        itr--;
        low.erase(itr);
    }
    
    if(r >= k-1) {
        
        cout << *low.rbegin() << " ";
        if(!low.empty() && low.count(a[l])) {
            low.erase(low.find(a[l]));
        }
        else if(!up.empty() && up.count(a[l])) {
            up.erase(up.find(a[l]));
        }
        l++;
    }
}
cout << "\n";

void ins(long val) {         // insert val into sets
    long a = *low.rbegin();  // current median
    if (a < val) {
        up.insert(val);
        if (up.size() > M / 2) {
            low.insert(*up.begin());
            up.erase(up.find(*up.begin()));
        }
    } else {
        low.insert(val);
        if (low.size() > (M + 1) / 2) {
            up.insert(*low.rbegin());
            low.erase(low.find(*low.rbegin()));
        }
    }
}

void er(long val) {  // erase from sets
    if (up.find(val) != up.end()) up.erase(up.find(val));
    else low.erase(low.find(val));
    if (low.empty()) {
        low.insert(*up.begin());
        up.erase(up.find(*up.begin()));
    }
}
low.insert(arr[0]);
for (int i = 1; i < M; i++) ins(arr[i]);
cout << *low.rbegin() << " ";
for (long i = M; i < N; i++) {
    if (M == 1) {
        ins(arr[i]);
        er(arr[i - M]);
    } else {
        er(arr[i - M]);
        ins(arr[i]);
    }
    cout << *low.rbegin() << " ";
}