結果

問題 No.1300 Sum of Inversions
ユーザー m_tsubasam_tsubasa
提出日時 2020-11-27 21:31:44
言語 C++17
(gcc 13.2.0 + boost 1.83.0)
結果
AC  
実行時間 358 ms / 2,000 ms
コード長 4,439 bytes
コンパイル時間 2,470 ms
コンパイル使用メモリ 219,164 KB
実行使用メモリ 20,272 KB
最終ジャッジ日時 2023-10-01 04:53:24
合計ジャッジ時間 13,301 ms
ジャッジサーバーID
（参考情報） 		judge14 / judge13
このコードへのチャレンジ（β）

テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 2 ms
4,384 KB
testcase_01 AC 2 ms
4,380 KB
testcase_02 AC 1 ms
4,376 KB
testcase_03 AC 275 ms
16,468 KB
testcase_04 AC 267 ms
15,724 KB
testcase_05 AC 214 ms
14,016 KB
testcase_06 AC 311 ms
17,908 KB
testcase_07 AC 305 ms
17,236 KB
testcase_08 AC 347 ms
18,520 KB
testcase_09 AC 345 ms
18,512 KB
testcase_10 AC 161 ms
11,936 KB
testcase_11 AC 178 ms
12,020 KB
testcase_12 AC 279 ms
15,928 KB
testcase_13 AC 256 ms
15,604 KB
testcase_14 AC 358 ms
19,928 KB
testcase_15 AC 330 ms
18,684 KB
testcase_16 AC 279 ms
16,644 KB
testcase_17 AC 156 ms
11,440 KB
testcase_18 AC 193 ms
12,884 KB
testcase_19 AC 231 ms
14,720 KB
testcase_20 AC 237 ms
14,828 KB
testcase_21 AC 236 ms
14,960 KB
testcase_22 AC 225 ms
13,668 KB
testcase_23 AC 313 ms
17,920 KB
testcase_24 AC 225 ms
14,008 KB
testcase_25 AC 176 ms
12,780 KB
testcase_26 AC 177 ms
12,320 KB
testcase_27 AC 203 ms
13,532 KB
testcase_28 AC 345 ms
19,412 KB
testcase_29 AC 222 ms
14,712 KB
testcase_30 AC 322 ms
18,588 KB
testcase_31 AC 201 ms
13,980 KB
testcase_32 AC 220 ms
14,040 KB
testcase_33 AC 74 ms
7,676 KB
testcase_34 AC 127 ms
7,720 KB
testcase_35 AC 199 ms
20,176 KB
testcase_36 AC 215 ms
20,272 KB
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 <bits/stdc++.h>
using namespace std;

template <int mod = (int)(998244353)>
struct ModInt {
  int x;
  ModInt() : x(0) {}
  ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
  ModInt &operator+=(const ModInt &p) {
    if ((x += p.x) >= mod) x -= mod;
    return *this;
  }
  ModInt &operator-=(const ModInt &p) {
    if ((x += mod - p.x) >= mod) x -= mod;
    return *this;
  }
  ModInt &operator*=(const ModInt &p) {
    x = (int)(1LL * x * p.x % mod);
    return *this;
  }
  ModInt &operator/=(const ModInt &p) {
    *this *= p.inverse();
    return *this;
  }
  ModInt operator-() const { return ModInt(-x); }
  ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
  ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
  ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
  ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
  bool operator==(const ModInt &p) const { return x == p.x; }
  bool operator!=(const ModInt &p) const { return x != p.x; }
  ModInt inverse() const {
    int a = x, b = mod, u = 1, v = 0, t;
    while (b > 0) {
      t = a / b;
      swap(a -= t * b, b);
      swap(u -= t * v, v);
    }
    return ModInt(u);
  }
  ModInt pow(int64_t n) const {
    ModInt res(1), mul(x);
    while (n) {
      if (n & 1) res *= mul;
      mul *= mul;
      n >>= 1;
    }
    return res;
  }
  friend ostream &operator<<(ostream &os, const ModInt &p) { return os << p.x; }
  friend istream &operator>>(istream &is, ModInt &a) {
    int64_t t;
    is >> t;
    a = ModInt<mod>(t);
    return (is);
  }
  static int get_mod() { return mod; }
};

struct Combination {
  vector<ModInt<>> _fact, _rfact, _inv;
  Combination(long long nsize = 5000000)
      : _fact(nsize + 1), _rfact(nsize + 1), _inv(nsize + 1) {
    _fact[0] = _rfact[nsize] = _inv[0] = 1;
    for (int i = 1; i <= nsize; i++) _fact[i] = _fact[i - 1] * i;
    _rfact[nsize] /= _fact[nsize];
    for (int i = nsize - 1; i >= 0; i--) _rfact[i] = _rfact[i + 1] * (i + 1);
    for (int i = 1; i <= nsize; i++) _inv[i] = _rfact[i] * _fact[i - 1];
  }
  inline ModInt<> fact(int k) const { return _fact[k]; }

  inline ModInt<> rfact(int k) const { return _rfact[k]; }

  inline ModInt<> inv(int k) const { return _inv[k]; }

  ModInt<> P(int n, int r) const {
    if (r < 0 || n < r) return 0;
    return fact(n) * rfact(n - r);
  }

  ModInt<> C(int p, int q) const {
    if (q < 0 || p < q) return 0;
    return fact(p) * rfact(q) * rfact(p - q);
  }

  ModInt<> largeC(long long p, long long q) const {
    if (q < 0 || p < q) return 0;
    ModInt<> res = rfact(q);
    for (int i = 0; i < q; ++i) res *= p - i;
    return res;
  }

  // n types,choose r
  ModInt<> H(int n, int r) const {
    if (n < 0 || r < 0) return (0);
    return r == 0 ? 1 : C(n + r - 1, r);
  }

  ModInt<> Catalan(int n) {
    // C(2n,n) / (n + 1)
    return fact(2 * n) * rfact(n + 1) * rfact(n);
  }
};
using mint = ModInt<>;

// 0-indexed
template <class T>
struct BIT {
  int treesize;
  vector<T> lst;
  // constructor
  BIT(int newn = 0) : treesize(newn), lst(newn + 1, 0) {}
  // a_place += num
  void add(int place, T num) {
    ++place;
    while (place <= treesize) {
      lst[place] += num;
      place += place & -place;
    }
  }
  // sum between [0,place)
  T sum(int place) {
    T res = 0;
    while (place > 0) {
      res += lst[place];
      place -= place & -place;
    }
    return res;
  }
  // sum [l,r)
  T sum(int left, int right) { return sum(right) - sum(left); }
};

int n;
BIT<mint> sum[2], cnt[2];
vector<long long> a;
map<long long, int> id;

mint solve();

int main() {
  cin >> n;
  a.resize(n);
  for (auto &p : a) cin >> p;
  {
    vector<long long> v;
    for (int i = 0; i < n; ++i) v.push_back(a[i]);
    sort(v.begin(), v.end());
    v.erase(unique(v.begin(), v.end()), v.end());
    int len = v.size();
    for (int i = 0; i < len; ++i) id[v[i]] = i;
  }
  cout << solve() << endl;
  return 0;
}

mint solve() {
  int len = id.size();
  mint res;
  sum[0] = cnt[0] = sum[1] = cnt[1] = BIT<mint>(n);
  for (int i = 0; i < n; ++i) {
    int nid = id[a[i]];
    mint nsum = sum[0].sum(nid + 1, len), ncnt = cnt[0].sum(nid + 1, len);
    res += sum[1].sum(nid + 1, len) + cnt[1].sum(nid + 1, len) * a[i];
    sum[1].add(nid, nsum + ncnt * a[i]);
    cnt[1].add(nid, ncnt);
    sum[0].add(nid, a[i]);
    cnt[0].add(nid, 1);
  }
  return res;
}
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