結果
問題 | No.1300 Sum of Inversions |
ユーザー | 👑 emthrm |
提出日時 | 2020-11-27 21:44:48 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 218 ms / 2,000 ms |
コード長 | 6,088 bytes |
コンパイル時間 | 2,373 ms |
コンパイル使用メモリ | 206,608 KB |
最終ジャッジ日時 | 2025-01-16 06:51:26 |
ジャッジサーバーID (参考情報) |
judge4 / judge5 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 3 |
other | AC * 34 |
ソースコード
#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;}