結果

問題 No.1300 Sum of Inversions
ユーザー 👑 emthrmemthrm
提出日時 2020-11-27 21:44:48
言語 C++17
(gcc 13.2.0 + boost 1.83.0)
結果
AC  
実行時間 198 ms / 2,000 ms
コード長 6,088 bytes
コンパイル時間 2,369 ms
コンパイル使用メモリ 210,840 KB
実行使用メモリ 7,928 KB
最終ジャッジ日時 2023-10-01 05:13:12
合計ジャッジ時間 8,585 ms
ジャッジサーバーID
（参考情報） 		judge12 / judge11
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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
4,376 KB
testcase_01 AC 2 ms
4,376 KB
testcase_02 AC 1 ms
4,380 KB
testcase_03 AC 156 ms
6,736 KB
testcase_04 AC 150 ms
6,552 KB
testcase_05 AC 122 ms
6,004 KB
testcase_06 AC 171 ms
7,036 KB
testcase_07 AC 165 ms
6,932 KB
testcase_08 AC 185 ms
7,244 KB
testcase_09 AC 183 ms
7,400 KB
testcase_10 AC 94 ms
5,600 KB
testcase_11 AC 98 ms
5,468 KB
testcase_12 AC 149 ms
6,504 KB
testcase_13 AC 152 ms
6,512 KB
testcase_14 AC 198 ms
7,716 KB
testcase_15 AC 185 ms
7,200 KB
testcase_16 AC 153 ms
6,732 KB
testcase_17 AC 93 ms
5,428 KB
testcase_18 AC 114 ms
5,664 KB
testcase_19 AC 130 ms
6,264 KB
testcase_20 AC 135 ms
6,148 KB
testcase_21 AC 131 ms
6,164 KB
testcase_22 AC 121 ms
5,976 KB
testcase_23 AC 167 ms
7,040 KB
testcase_24 AC 126 ms
5,980 KB
testcase_25 AC 103 ms
5,860 KB
testcase_26 AC 103 ms
5,612 KB
testcase_27 AC 116 ms
5,864 KB
testcase_28 AC 190 ms
7,536 KB
testcase_29 AC 129 ms
6,132 KB
testcase_30 AC 186 ms
7,192 KB
testcase_31 AC 119 ms
5,900 KB
testcase_32 AC 131 ms
6,256 KB
testcase_33 AC 22 ms
4,556 KB
testcase_34 AC 35 ms
4,640 KB
testcase_35 AC 120 ms
7,772 KB
testcase_36 AC 124 ms
7,928 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 # 

#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
constexpr int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
constexpr int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

template <int MOD>
struct MInt {
  unsigned val;
  MInt(): val(0) {}
  MInt(long long x) : val(x >= 0 ? x % MOD : x % MOD + MOD) {}
  static int get_mod() { return MOD; }
  static void set_mod(int divisor) { assert(divisor == MOD); }
  MInt pow(long long exponent) const {
    MInt tmp = *this, res = 1;
    while (exponent > 0) {
      if (exponent & 1) res *= tmp;
      tmp *= tmp;
      exponent >>= 1;
    }
    return res;
  }
  MInt &operator+=(const MInt &x) { if((val += x.val) >= MOD) val -= MOD; return *this; }
  MInt &operator-=(const MInt &x) { if((val += MOD - x.val) >= MOD) val -= MOD; return *this; }
  MInt &operator*=(const MInt &x) { val = static_cast<unsigned long long>(val) * x.val % MOD; return *this; }
  MInt &operator/=(const MInt &x) {
    // assert(std::__gcd(static_cast<int>(x.val), MOD) == 1);
    unsigned a = x.val, b = MOD; int u = 1, v = 0;
    while (b) {
      unsigned tmp = a / b;
      std::swap(a -= tmp * b, b);
      std::swap(u -= tmp * v, v);
    }
    return *this *= u;
  }
  bool operator==(const MInt &x) const { return val == x.val; }
  bool operator!=(const MInt &x) const { return val != x.val; }
  bool operator<(const MInt &x) const { return val < x.val; }
  bool operator<=(const MInt &x) const { return val <= x.val; }
  bool operator>(const MInt &x) const { return val > x.val; }
  bool operator>=(const MInt &x) const { return val >= x.val; }
  MInt &operator++() { if (++val == MOD) val = 0; return *this; }
  MInt operator++(int) { MInt res = *this; ++*this; return res; }
  MInt &operator--() { val = (val == 0 ? MOD : val) - 1; return *this; }
  MInt operator--(int) { MInt res = *this; --*this; return res; }
  MInt operator+() const { return *this; }
  MInt operator-() const { return MInt(val ? MOD - val : 0); }
  MInt operator+(const MInt &x) const { return MInt(*this) += x; }
  MInt operator-(const MInt &x) const { return MInt(*this) -= x; }
  MInt operator*(const MInt &x) const { return MInt(*this) *= x; }
  MInt operator/(const MInt &x) const { return MInt(*this) /= x; }
  friend std::ostream &operator<<(std::ostream &os, const MInt &x) { return os << x.val; }
  friend std::istream &operator>>(std::istream &is, MInt &x) { long long val; is >> val; x = MInt(val); return is; }
};
namespace std { template <int MOD> MInt<MOD> abs(const MInt<MOD> &x) { return x; } }
template <int MOD>
struct Combinatorics {
  using ModInt = MInt<MOD>;
  int val;  // "val!" and "mod" must be disjoint.
  std::vector<ModInt> fact, fact_inv, inv;
  Combinatorics(int val = 10000000) : val(val), fact(val + 1), fact_inv(val + 1), inv(val + 1) {
    fact[0] = 1;
    for (int i = 1; i <= val; ++i) fact[i] = fact[i - 1] * i;
    fact_inv[val] = ModInt(1) / fact[val];
    for (int i = val; i > 0; --i) fact_inv[i - 1] = fact_inv[i] * i;
    for (int i = 1; i <= val; ++i) inv[i] = fact[i - 1] * fact_inv[i];
  }
  ModInt nCk(int n, int k) const {
    if (n < 0 || n < k || k < 0) return 0;
    assert(n <= val && k <= val);
    return fact[n] * fact_inv[k] * fact_inv[n - k];
  }
  ModInt nPk(int n, int k) const {
    if (n < 0 || n < k || k < 0) return 0;
    assert(n <= val);
    return fact[n] * fact_inv[n - k];
  }
  ModInt nHk(int n, int k) const {
    if (n < 0 || k < 0) return 0;
    return k == 0 ? 1 : nCk(n + k - 1, k);
  }
};
using ModInt = MInt<MOD>;

template <typename Abelian>
struct BIT {
  BIT(int n, const Abelian UNITY = 0) : n(n), UNITY(UNITY), dat(n, UNITY) {}

  void add(int idx, Abelian val) {
    while (idx < n) {
      dat[idx] += val;
      idx |= idx + 1;
    }
  }

  Abelian sum(int idx) const {
    Abelian res = UNITY;
    --idx;
    while (idx >= 0) {
      res += dat[idx];
      idx = (idx & (idx + 1)) - 1;
    }
    return res;
  }

  Abelian sum(int left, int right) const {
    return left < right ? sum(right) - sum(left) : UNITY;
  }

  Abelian operator[](const int idx) const { return sum(idx, idx + 1); }

  int lower_bound(Abelian val) const {
    if (val <= UNITY) return 0;
    int res = 0, exponent = 1;
    while (exponent <= n) exponent <<= 1;
    for (int mask = exponent >> 1; mask > 0; mask >>= 1) {
      if (res + mask - 1 < n && dat[res + mask - 1] < val) {
        val -= dat[res + mask - 1];
        res += mask;
      }
    }
    return res;
  }

private:
  int n;
  const Abelian UNITY;
  std::vector<Abelian> dat;
};

int main() {
  int n; cin >> n;
  vector<int> a(n); REP(i, n) cin >> a[i];
  vector<int> b(a);
  sort(ALL(b));
  b.erase(unique(ALL(b)), b.end());
  int m = b.size();
  BIT<ModInt> bit1(m), bit3(m), bit4(m);
  BIT<int> bit2(m);
  REP(i, n) {
    int idx = lower_bound(ALL(b), a[i]) - b.begin();
    bit3.add(idx, bit1.sum(idx + 1, m));
    int cnt = bit2.sum(idx + 1, m);
    bit3.add(idx, 1LL * a[i] * cnt);
    bit4.add(idx, cnt);
    bit1.add(idx, a[i]);
    bit2.add(idx, 1);
  }
  ModInt ans = 0;
  for (int i = n - 1; i >= 0; --i) {
    int idx = lower_bound(ALL(b), a[i]) - b.begin();
    bit1.add(idx, -a[i]);
    bit2.add(idx, -1);
    bit3.add(idx, -bit1.sum(idx + 1, m));
    int cnt = bit2.sum(idx + 1, m);
    bit3.add(idx, -1LL * a[i] * cnt);
    bit4.add(idx, -cnt);
    ans += bit3.sum(idx + 1, m) + bit4.sum(idx + 1, m) * a[i];
  }
  cout << ans << '\n';
  return 0;
}
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