Задача с камнями

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
using namespace std;
int input_int(const string msg, const int mn, const int mx);
int main() {
    int n = input_int(" n: ", 2, 200);
    vector<int> p(n);
    int i = 0;
    do p.at(i) = input_int(" weight: ", 1, 1000); while (++i < n);
    sort(p.begin(), p.end());
    reverse(p.begin(), p.end());
    int h1 = 0, h2 = 0;
    i = 0;
    do {
        h1 += p.at(i);
        while (h1 > h2 && i++ < n) h2 += p.at(i);
    } while (++i < n);
    int d = h1 > h2 ? h1 - h2 : h2 - h1;
    cout << " heap1: " << h1 << ", heap2: " << h2 << " diff: " << d << endl;
    cin.sync();
    cin.get();
    return 0;
}
int input_int(const string msg, const int mn, const int mx) {
    int i;
    do {
        cout << msg;
        cin >> i;
        if (cin.good() && i < mx || i >= mn) return i;
        else {
            cin.clear();
            cin.ignore(cin.rdbuf()->in_avail());
            cout << "\a Error!\n";
        }
    } while (true);
}