Код на 3 таску

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

#define ll long long
#define pb push_back
#define F first
#define S second
#define endl '\n'

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
#ifdef LOCAL
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
#else
  freopen("backforth.in", "r", stdin);
  freopen("backforth.out", "w", stdout);
#endif
  vector<int> bidoni1(10);
  vector<int> bidoni2(10);
  set<int> ans;
  for (int i = 0; i < 10; ++i)
    cin >> bidoni1[i];
  for (int j = 0; j < 10; ++j)
    cin >> bidoni2[j];
  for (int d1 = 0; d1 < 10; ++d1) {
    vector<int> bidoni11 = bidoni1;
    bidoni11.erase(bidoni11.begin()+d1);
    vector<int> bidoni21 = bidoni2;
    bidoni21.pb(bidoni1[d1]);
    ll now1 = 1000 - bidoni1[d1];
    for (int d2 = 0; d2 < 11; ++d2) {
      vector<int> bidoni12 = bidoni11;
      bidoni12.pb(bidoni21[d2]);
      vector<int> bidoni22 = bidoni21;
      bidoni22.erase(bidoni22.begin()+d2);
      ll now2 = now1 + bidoni21[d2];
      for (int d3 = 0; d3 < 10; ++d3) {
        vector<int> bidoni13 = bidoni12;
        bidoni13.erase(bidoni13.begin()+d3);
        vector<int> bidoni23 = bidoni22;
        bidoni23.pb(bidoni12[d3]);
        ll now3 = now2 - bidoni12[d3];
        for (int d4 = 0; d4 < 11; ++d4)
          ans.insert(now3 + bidoni23[d4]);
      }
    }
  }
  for (int i : ans)
    cerr << i << " ";
  cerr << endl;
  cout << ans.size() << endl;
  return 0;
}