結果

問題 No.1282 Display Elements
コンテスト
ユーザー platinum
提出日時 2020-11-05 13:59:49
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 122 ms / 2,000 ms
コード長 5,096 bytes
コンパイル時間 741 ms
コンパイル使用メモリ 80,172 KB
実行使用メモリ 5,760 KB
最終ジャッジ日時 2024-07-22 11:09:44
合計ジャッジ時間 3,277 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge3
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ファイルパターン 結果
other AC * 24
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <iostream>
#include <cassert>
#include <vector>
#include <algorithm>
#include <numeric>
#include <type_traits>

namespace atcoder {

namespace internal {

#ifndef _MSC_VER
template <class T>
using is_signed_int128 =
    typename std::conditional<std::is_same<T, __int128_t>::value ||
                                  std::is_same<T, __int128>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using is_unsigned_int128 =
    typename std::conditional<std::is_same<T, __uint128_t>::value ||
                                  std::is_same<T, unsigned __int128>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using make_unsigned_int128 =
    typename std::conditional<std::is_same<T, __int128_t>::value,
                              __uint128_t,
                              unsigned __int128>;

template <class T>
using is_integral = typename std::conditional<std::is_integral<T>::value ||
                                                  is_signed_int128<T>::value ||
                                                  is_unsigned_int128<T>::value,
                                              std::true_type,
                                              std::false_type>::type;

template <class T>
using is_signed_int = typename std::conditional<(is_integral<T>::value &&
                                                 std::is_signed<T>::value) ||
                                                    is_signed_int128<T>::value,
                                                std::true_type,
                                                std::false_type>::type;

template <class T>
using is_unsigned_int =
    typename std::conditional<(is_integral<T>::value &&
                               std::is_unsigned<T>::value) ||
                                  is_unsigned_int128<T>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using to_unsigned = typename std::conditional<
    is_signed_int128<T>::value,
    make_unsigned_int128<T>,
    typename std::conditional<std::is_signed<T>::value,
                              std::make_unsigned<T>,
                              std::common_type<T>>::type>::type;

#else

template <class T> using is_integral = typename std::is_integral<T>;

template <class T>
using is_signed_int =
    typename std::conditional<is_integral<T>::value && std::is_signed<T>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using is_unsigned_int =
    typename std::conditional<is_integral<T>::value &&
                                  std::is_unsigned<T>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using to_unsigned = typename std::conditional<is_signed_int<T>::value,
                                              std::make_unsigned<T>,
                                              std::common_type<T>>::type;

#endif

template <class T>
using is_signed_int_t = std::enable_if_t<is_signed_int<T>::value>;

template <class T>
using is_unsigned_int_t = std::enable_if_t<is_unsigned_int<T>::value>;

template <class T> using to_unsigned_t = typename to_unsigned<T>::type;

}  // namespace internal

}  // namespace atcoder

namespace atcoder {

// Reference: https://en.wikipedia.org/wiki/Fenwick_tree
template <class T> struct fenwick_tree {
    using U = internal::to_unsigned_t<T>;

  public:
    fenwick_tree() : _n(0) {}
    fenwick_tree(int n) : _n(n), data(n) {}

    void add(int p, T x) {
        assert(0 <= p && p < _n);
        p++;
        while (p <= _n) {
            data[p - 1] += U(x);
            p += p & -p;
        }
    }

    T sum(int l, int r) {
        assert(0 <= l && l <= r && r <= _n);
        return sum(r) - sum(l);
    }

  private:
    int _n;
    std::vector<U> data;

    U sum(int r) {
        U s = 0;
        while (r > 0) {
            s += data[r - 1];
            r -= r & -r;
        }
        return s;
    }
};

}  // namespace atcoder

#define rep(i,n) for(int i=0; i<(int)(n); i++)

using namespace std;
using namespace atcoder;
using LL = long long;
const int Max_N = 1e5;
const int Max_A = 1e9;

int main(){
  int N;
  cin >> N;
  assert(1 <= N and N <= Max_N);
  vector<int> a(N), b(N);
  rep(i,N) cin >> a[i];
  rep(i,N) assert(1 <= a[i] and a[i] <= Max_A);
  rep(i,N) cin >> b[i];
  rep(i,N) assert(1 <= b[i] and b[i] <= Max_A);
  vector<int> c(2 * N);
  rep(i,N) c[i] = a[i];
  rep(i,N) c[N + i] = b[i];
  sort(c.begin(), c.end());
  c.erase(unique(c.begin(), c.end()), c.end());
  sort(a.begin(), a.end());
  rep(i,N) a[i] = lower_bound(c.begin(), c.end(), a[i]) - c.begin();
  rep(i,N) b[i] = lower_bound(c.begin(), c.end(), b[i]) - c.begin();
  fenwick_tree<int> ft(2 * N);
  LL ans = 0;
  rep(i,N){
    ft.add(b[i], 1);
    ans += ft.sum(0, a[i]);
  }
  cout << ans << endl;

  return 0;
}
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