Submission #3514217

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Source Code Expand

#include <bits/stdc++.h>
#define int long long
#define rep(i, n) for (int i = 1; i <= (n); i ++) 
using namespace std;

inline void fastio(void) {
  ios::sync_with_stdio(0);
  cin.tie(0); cout.tie(0);
}
template <typename T>
inline void read(T &x) {
  cin >> x;
}

namespace {
  const int mo = 1e9 + 7;
  inline int add(int x, int y) {
    if((x += y) >= mo) x -= mo;
    return x;
  }
  inline int sub(int x, int y) {
    if((x -= y) < 0) x += mo;
    return x;
  }
  inline int mul(int x, int y) {
    return 1LL * x * y % mo;
  }
  inline int pw(int a, int k) {
    int ans = 1;
    for (; k; k >>= 1, a = mul(a, a))
      if (k & 1) ans = mul(ans, a);
    return ans;
  }
}
const int N = 3e5 + 233;
int n, m, x;
pair <int, int> a[N];

signed main(void) {
  fastio();
  cin >> n;
  rep (i, n) cin >> x, a[++ m] = {x, 0};
  rep (i, n) cin >> x, a[++ m] = {x, 1};
  sort(a + 1, a + m + 1);
  int x = 0, y = 0, ans = 1;
  for (int i = 1; i <= m; i ++) {
    if (a[i].second == 0) {
      if (y) ans *= y --;
      else x ++;
    } else {
      if (x) ans *= x --;
      else y ++;
    }
    ans %= mo;
  }
  cout << ans << "\n";
}

Submission Info

Judge Result