Language: C++

#include <bits/stdc++.h>
using namespace std;
 
#define int long long
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define FOR(i,a,b) for(int (i)=(a);(i)<(b);(i)++)
#define REP(i,n) FOR(i,0,n)
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define SORT(c) sort((c).begin(),(c).end())
#define ve vector
#define vi vector<int>
#define vp vector<pair<int,int>>
#define vvi vector<vector<int>>
 
typedef long long ll;
const ll INF = LLONG_MAX - 100;
const ll mod = 1e9 + 7;
const int MAX_N = 2e5 + 5;
int dx[] = {-1,0,1,0}, dy[] = {0,1,0,-1};
vector<ll> prime;
 
int fac[MAX_N], inv[MAX_N];
 
template <class T = ll> T in() {T x; cin >> x; return (x);}
void DEBUG(vector<int> a) {for(int i=0;i<a.size();i++){cout<<a[i]<<" ";cout<<endl;}}
ll GCD(ll a, ll b) {ll c; while (b != 0) {c = a % b; a = b; b = c;}return a;}
ll LCM(ll a, ll b) {return a * b / GCD(a, b);}
ll POW(ll a, ll b) {ll c = 1LL; while (b > 0) {if (b & 1LL) {c = a * c%mod;}a = a * a%mod; b >>= 1LL;}return c;}
void _nCr() {fac[0] = 1LL; for (int i = 1LL; i < MAX_N; i++) {fac[i] = fac[i - 1LL] * i%mod;}for (int i = 0; i < MAX_N; i++) {inv[i] = POW(fac[i], mod - 2);}}
ll nCr(ll n, ll r) {return (fac[n] * inv[r] % mod)*inv[n - r] % mod;}
void PRI(ll n) {bool a[n + 1LL]; for (int i = 0; i < n + 1LL; i++) {a[i] = 1LL;}for (int i = 2; i < n + 1LL; i++) {if (a[i]) {prime.pb(i); ll b = i; while (b <= n) {a[b] = 0; b += i;}}}}
template <typename T> T chmin(T& a, T b) {if(a>b)a=b;return a;}
template <typename T> T chmax(T& a, T b) {if(a<b)a=b;return b;}

bool solve() {
	int n; cin >> n;
	vp A(n);
	REP (i,n) {
		int x; cin >> x; A.pb(x,1);
	}
	REP (i,n) {
		int x; cin >> x; A.pb(x,-1);
	}
	sort(ALL(A));
	int ans = 1;
	int cnt = 0;
	for (auto a : A) {
		int delta = a.second;
		if (cnt != 0 && (cnt > 0) != a.second) {
			ans *= abs(cnt); ans %= mod;
		}
		cnt += delta;
	}
	cout << ans << endl;
}

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	solve();
}

Compiler output:
a.cc: In function 'bool solve()':
a.cc:43:38: error: no matching function for call to 'std::vector<std::pair<long long int, long long int> >::push_back(long long int&, int)'
   43 |                 int x; cin >> x; A.pb(x,1);
      |                                  ~~~~^~~~~
In file included from /usr/include/c++/14/vector:66,
                 from /usr/include/c++/14/functional:64,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_vector.h:1283:7: note: candidate: 'void std::vector<_Tp, _Alloc>::push_back(const value_type&) [with _Tp = std::pair<long long int, long long int>; _Alloc = std::allocator<std::pair<long long int, long long int> >; value_type = std::pair<long long int, long long int>]'
 1283 |       push_back(const value_type& __x)
      |       ^~~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1283:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:1300:7: note: candidate: 'void std::vector<_Tp, _Alloc>::push_back(value_type&&) [with _Tp = std::pair<long long int, long long int>; _Alloc = std::allocator<std::pair<long long int, long long int> >; value_type = std::pair<long long int, long long int>]'
 1300 |       push_back(value_type&& __x)
      |       ^~~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1300:7: note:   candidate expects 1 argument, 2 provided
a.cc:46:38: error: no matching function for call to 'std::vector<std::pair<long long int, long long int> >::push_back(long long int&, int)'
   46 |                 int x; cin >> x; A.pb(x,-1);
      |                                  ~~~~^~~~~~
/usr/include/c++/14/bits/stl_vector.h:1283:7: note: candidate: 'void std::vector<_Tp, _Alloc>::push_back(const value_type&) [with _Tp = std::pair<long long int, long long int>; _Alloc = std::allocator<std::pair<long long int, long long int> >; value_type = std::pair<long long int, long long int>]'
 1283 |       push_back(const value_type& __x)
      |       ^~~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1283:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:1300:7: note: candidate: 'void std::vector<_Tp, _Alloc>::push_back(value_type&&) [with _Tp = std::pair<long long int, long long int>; _Alloc = std::allocator<std::pair<long long int, long long int> >; value_type = std::pair<long long int, long long int>]'
 1300 |       push_back(value_type&& __x)
      |       ^~~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:1300:7: note:   candidate expects 1 argument, 2 provided
a.cc:59:1: warning: no return statement in function returning non-void [-Wreturn-type]
   59 | }
      | ^