結果

問題 No.1300 Sum of Inversions
ユーザー chocopuu
提出日時 2020-11-27 21:56:14
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 485 ms / 2,000 ms
コード長 6,519 bytes
コンパイル時間 2,693 ms
コンパイル使用メモリ 212,036 KB
最終ジャッジ日時 2025-01-16 07:09:02
ジャッジサーバーID
（参考情報） 		judge5 / judge1
このコードへのチャレンジ
（要ログイン）
ファイルパターン 結果
sample AC * 3
other AC * 34
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 #
プレゼンテーションモードにする

#include "bits/stdc++.h"
using namespace std;
//#include "atcoder/all"
//using namespace atcoder;
#define int long long
#define REP(i, n) for (int i = 0; i < (int)n; ++i)
#define RREP(i, n) for (int i = (int)n - 1; i >= 0; --i)
#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define RFOR(i, s, n) for (int i = (int)n - 1; i >= s; --i)
#define ALL(a) a.begin(), a.end()
#define IN(a, x, b) (a <= x && x < b)
template<class T>istream&operator >>(istream&is,vector<T>&vec){for(T&x:vec)is>>x;return is;}
template<class T>inline void out(T t){cout << t << "\n";}
template<class T,class... Ts>inline void out(T t,Ts... ts){cout << t << " ";out(ts...);}
template<class T>inline bool CHMIN(T&a,T b){if(a > b){a = b;return true;}return false;}
template<class T>inline bool CHMAX(T&a,T b){if(a < b){a = b;return true;}return false;}
constexpr int INF = 1e18;
template<int MOD> struct Fp {
    long long val;
    constexpr Fp(long long v = 0) noexcept : val(v % MOD) {
        if (val < 0) val += MOD;
    }
    constexpr int getmod() { return MOD; }
    constexpr Fp operator - () const noexcept {
        return val ? MOD - val : 0;
    }
    constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; }
    constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; }
    constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; }
    constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; }
    constexpr Fp& operator += (const Fp& r) noexcept {
        val += r.val;
        if (val >= MOD) val -= MOD;
        return *this;
    }
    constexpr Fp& operator -= (const Fp& r) noexcept {
        val -= r.val;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr Fp& operator *= (const Fp& r) noexcept {
        val = val * r.val % MOD;
        return *this;
    }
    constexpr Fp& operator /= (const Fp& r) noexcept {
        long long a = r.val, b = MOD, u = 1, v = 0;
        while (b) {
            long long t = a / b;
            a -= t * b; swap(a, b);
            u -= t * v; swap(u, v);
        }
        val = val * u % MOD;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr bool operator == (const Fp& r) const noexcept {
        return this->val == r.val;
    }
    constexpr bool operator != (const Fp& r) const noexcept {
        return this->val != r.val;
    }
    friend constexpr ostream& operator << (ostream &os, const Fp<MOD>& x) noexcept {
        return os << x.val;
    }
    friend constexpr Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept {
        if (n == 0) return 1;
        auto t = modpow(a, n / 2);
        t = t * t;
        if (n & 1) t = t * a;
        return t;
    }
};
 
template<class T> struct BiCoef {
    vector<T> fact_, inv_, finv_;
    constexpr BiCoef() {}
    constexpr BiCoef(int n) noexcept : fact_(n, 1), inv_(n, 1), finv_(n, 1) {
        init(n);
    }
    constexpr void init(int n) noexcept {
        fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1);
        int MOD = fact_[0].getmod();
        for(int i = 2; i < n; i++){
            fact_[i] = fact_[i-1] * i;
            inv_[i] = -inv_[MOD%i] * (MOD/i);
            finv_[i] = finv_[i-1] * inv_[i];
        }
    }
    constexpr T com(int n, int k) const noexcept {
        if (n < k || n < 0 || k < 0) return 0;
        return fact_[n] * finv_[k] * finv_[n-k];
    }
    constexpr T P(int n, int k) const noexcept {
        if (n < k || n < 0 || k < 0) return 0;
        return fact_[n] * finv_[n-k];
    }
    constexpr T fact(int n) const noexcept {
        if (n < 0) return 0;
        return fact_[n];
    }
    constexpr T inv(int n) const noexcept {
        if (n < 0) return 0;
        return inv_[n];
    }
    constexpr T finv(int n) const noexcept {
        if (n < 0) return 0;
        return finv_[n];
    }
};
 
// const int MOD = 1000000007;
const int MOD = 998244353;
using mint = Fp<MOD>;
BiCoef<mint> bc;
// bc.init(500050);
template <typename T>
struct SegmentTree{
  using F = function<T(T,T)>;
  int n;
  F f;
  T ti;
  vector<T> dat;
  SegmentTree(){}
  SegmentTree(F f,T ti):f(f),ti(ti){}
  void init(int n_){
    n=1;
    while(n<n_) n<<=1;
    dat.assign(n<<1,ti);
  }
  void build(const vector<T> &v){
    int n_=v.size();
    init(n_);
    for(int i=0;i<n_;i++) dat[n+i]=v[i];
    for(int i=n-1;i;i--)
      dat[i]=f(dat[(i<<1)|0],dat[(i<<1)|1]);
  }
  void set_val(int k,T x){
    dat[k+=n]=x;
    while(k>>=1)
      dat[k]=f(dat[(k<<1)|0],dat[(k<<1)|1]);
  }
  T query(int a,int b){
    if(a>=b) return ti;
    T vl=ti,vr=ti;
    for(int l=a+n,r=b+n;l<r;l>>=1,r>>=1) {
      if(l&1) vl=f(vl,dat[l++]);
      if(r&1) vr=f(dat[--r],vr);
    }
    return f(vl,vr);
  }
  template<typename C>
  int find(int st,C &check,T &acc,int k,int l,int r){
    if(l+1==r){
      acc=f(acc,dat[k]);
      return check(acc)?k-n:-1;
    }
    int m=(l+r)>>1;
    if(m<=st) return find(st,check,acc,(k<<1)|1,m,r);
    if(st<=l&&!check(f(acc,dat[k]))){
      acc=f(acc,dat[k]);
      return -1;
    }
    int vl=find(st,check,acc,(k<<1)|0,l,m);
    if(~vl) return vl;
    return find(st,check,acc,(k<<1)|1,m,r);
  }
  template<typename C>
  int find(int st,C &check){
    T acc=ti;
    return find(st,check,acc,1,0,n);
  }
  //アウトの条件を渡す
};
template< typename T >
struct Compress {
  vector< T > xs;
  Compress() = default;
  Compress(const vector< T > &vs) {
    add(vs);
  }
  Compress(const initializer_list< vector< T > > &vs) {
    for(auto &p : vs) add(p);
  }
  void add(const vector< T > &vs) {
    copy(begin(vs), end(vs), back_inserter(xs));
  }
  void add(const T &x) {
    xs.emplace_back(x);
  }
  void build() {
    sort(begin(xs), end(xs));
    xs.erase(unique(begin(xs), end(xs)), end(xs));
  }
  vector< int > get(const vector< T > &vs) const {
    vector< int > ret;
    transform(begin(vs), end(vs), back_inserter(ret), [&](const T &x) {
      return lower_bound(begin(xs), end(xs), x) - begin(xs);
    });
    return ret;
  }
  int get(const T &x) const {
    return lower_bound(begin(xs), end(xs), x) - begin(xs);
  }
  const T &operator[](int k) const {
    return xs[k];
  }
};
signed main(){
    int N;
    cin >> N;
    vector<int> a(N);
    cin >> a;
    Compress c(a);
    c.build();
    SegmentTree<pair<mint, int>>l([](pair<mint, int> a, pair<mint, int> b) {return pair<mint, int>(a.first + b.first, a.second + b.second);}, {mint(0
        ), 0});
    l.build(vector<pair<mint,int>>(c.xs.size()));
    auto r = l;
    REP(i, N) {
        int pos = c.get(a[i]);
        auto p = r.query(pos, pos + 1);
        r.set_val(pos, {p.first + a[i], p.second + 1});
    }
    mint ans = 0;
    REP(i, N) {
        int pos = c.get(a[i]);
        auto lval = l.query(pos + 1, c.xs.size());
        auto rval = r.query(0, pos);
        ans += lval.first * rval.second;
        ans += rval.first * lval.second;
        ans += rval.second * lval.second % MOD * a[i];
        auto lp = l.query(pos, pos + 1);
        l.set_val(pos, {lp.first + a[i], lp.second + 1});
        auto rp = r.query(pos, pos + 1);
        r.set_val(pos, {rp.first - a[i], rp.second - 1});
    }
    out(ans);
}
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
0