Language: C++

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;

#define REP(i,n) for(long long i = 0; i < (n); i++)
#define FOR(i, m, n) for(long long i = (m);i < (n); ++i)
#define ALL(obj) (obj).begin(),(obj).end()
#define SPEED cin.tie(0);ios::sync_with_stdio(false);

template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQR = priority_queue<T,vector<T>,greater<T>>;

const ll MOD = (ll)1e9 + 7;
const ll MOD2 = 998244353;
const ll HIGHINF = (ll)1e18;
const ll LOWINF = (ll)1e15;
const long double PI = 3.1415926535897932384626433;

template<typename T> vector<T> make_v(size_t N,T init){return vector<T>(N,init);}
template<typename... T> auto make_v(size_t N,T... t){return vector<decltype(make_v(t...))>(N,make_v(t...));}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}}
template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;}
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}
template <class T> void chmax(T& a, const T b){a=max<T>(a,b);}
template <class T> void chmin(T& a, const T b){a=min<T>(a,b);}
void YN(bool flg) {cout << ((flg) ? "YES" : "NO") << endl;}
void Yn(bool flg) {cout << ((flg) ? "Yes" : "No") << endl;}
void yn(bool flg) {cout << ((flg) ? "yes" : "no") << endl;}


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

//Seat Pressure O(NlogN)
template<class T> vector<ll> Zarts(const vector<T> & ar, int cnt = 0) {
    vector<int> res;
    map<T, int> mp;
    for (auto &e : ar) mp[e] = 0;
    for (auto &e : mp) e.second = cnt++;
    for (auto &e : ar) res.push_back(mp[e]);
    return res;
}


int main() {

  ll N;
  V<ll> a(N),b(N),c(N),d;
  REP(i,N)cin>>a[i];
  REP(i,N)cin>>b[i];
  REP(i,N)cin>>c[i];
  
  REP(i,N)d.push_back(a[i]);
  REP(i,N)d.push_back(b[i]);
  REP(i,N)d.push_back(c[i]);
  
  d=Zarts<ll>(d);
  
  V<ll> e(3*N,0),f(3*N,0),g(3*N,0);
  REP(i,N)e[d[i]]++;
  FOR(i,N,2*N)f[d[i]]++;
  FOR(i,2*N,3*N)g[d[i]]++;
  
  for(int i = 0;i<3*N-1;++i)e[i+1]+=e[i];
  for(int i = 3*N-1;0<i;--i)g[i-1]+=g[i];
  ll ans=0;
  for(int i = 1;i<3*N-1;++i)ans+=e[i-1]*f[i]*g[i+1];
  cout<<ans<<endl;
  
  
  
  
    


    return 0;
}


Compiler output:
a.cc: In function 'std::vector<long long int> Zarts(const std::vector<_Tp>&, int)':
a.cc:51:12: error: could not convert 'static_cast<std::vector<int>&&>(res)' from 'vector<int>' to 'vector<long long int>'
   51 |     return res;
      |            ^~~
      |            |
      |            vector<int>