Raspored [државен '10] (nedovrseno)

#include <bits/stdc++.h>
using namespace std;

int main() {
    int g, n, m; cin >> g >> n >> m;
    multiset<int> gr;
    for (int i = 0; i < g; ++i) {
        int p; cin >> p;
        _test += p;
        gr.insert(p);
    }
    int broj = 0;
    auto f = gr.begin();
    auto b = prev(gr.end());
    int fv = *f, bv = *b;
    while (true) {
        f = gr.begin();
        b = prev(gr.end());
        fv = *f;
        bv = *b;
        if (fv >= n && bv <= m) {
            break;
        }
        bool changed = false;
        if (fv < n) {
            changed = true;
            int chng = n - fv;
            bv = bv - chng;
            fv = n;
            broj += chng;
            gr.erase(f);
            gr.erase(b);
            gr.insert(fv);
            gr.insert(bv);
//          cout << "fv<n chng=" << chng << " | ";
//          int _s = 0;
//          for (auto it : gr) {
//             cout << it << " "; _s += it;
//          }
//          cout << "(" << _s << ")" << endl;
        }
        f = gr.begin();
        b = prev(gr.end());
        fv = *f;
        bv = *b;
        if (bv > m) {
            changed = true;
            int chng = bv - m;
            fv = fv + chng;
            bv = m;
            gr.erase(f);
            gr.erase(b);
            gr.insert(fv);
            gr.insert(bv);
//            cout << "bv>m chng=" << chng << " | ";
//            int _s = 0;
//            for (auto it : gr) {
//                cout << it << " "; _s += it;
//            }
//            cout << "(" << _s << ")" << endl;
        }
        if (!changed) {
            broj = -1;
            break;
        }
    }
    cout << broj << endl;
}