#598587 (C++17) No.1300 Sum of Inversions

• 問題: No.1300 Sum of Inversions
• ユーザー: Chanyuh
• 提出日時: 2020-12-31 17:01:48
• 言語: C++17 (gcc 13.3.0 + boost 1.87.0)
• 結果: AC
• 実行時間: 223 ms / 2,000 ms
• コード長: 7,685 bytes
• コンパイル時間: 1,369 ms
• コンパイル使用メモリ: 134,108 KB
• 最終ジャッジ日時: 2025-01-17 08:47:30
• ジャッジサーバーID （参考情報）: judge4 / judge4

ファイルパターン	結果
sample	AC * 3
other	AC * 34

ソースコード

#include<iostream>
#include<array>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<complex>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<tuple>
#include<cassert>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = 998244353;
const ll INF = (ll)1000000007 * 1000000007;
typedef pair<int, int> P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define Per(i,sta,n) for(int i=n-1;i>=sta;i--)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
typedef long double ld;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<ll, ll> LP;
int dx[4]={1,-1,0,0};
int dy[4]={0,0,1,-1};
template<class T>bool chmax(T &a, const T &b) {if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T &a, const T &b) {if(b<a){a=b;return 1;}return 0;}

template <class S, S (*op)(S, S), S (*e)()> struct SegmentTree {
  public:
    SegmentTree() : SegmentTree(0) {}
    SegmentTree(int n) : SegmentTree(std::vector<S>(n, e())) {}
    SegmentTree(const std::vector<S>& v) : _n(int(v.size())) {
        log = ceil_pow2(_n);
        size = 1 << log;
        d = std::vector<S>(2 * size, e());
        for (int i = 0; i < _n; i++) d[size + i] = v[i];
        for (int i = size - 1; i >= 1; i--) {
            update(i);
        }
    }

    void set_val(int p, S x) {
        assert(0 <= p && p < _n);
        p += size;
        d[p] = x;
        for (int i = 1; i <= log; i++) update(p >> i);
    }

    S get(int p) {
        assert(0 <= p && p < _n);
        return d[p + size];
    }

    S query(int l, int r) {
        assert(0 <= l && l <= r && r <= _n);
        S sml = e(), smr = e();
        l += size;
        r += size;

        while (l < r) {
            if (l & 1) sml = op(sml, d[l++]);
            if (r & 1) smr = op(d[--r], smr);
            l >>= 1;
            r >>= 1;
        }
        return op(sml, smr);
    }

    S all_query() { return d[1]; }

    template <bool (*f)(S)> int max_right(int l) {//f(op([l,r)))==trueを満たす最大のr
        return max_right(l, [](S x) { return f(x); });
    }
    template <class F> int max_right(int l, F f) {
        assert(0 <= l && l <= _n);
        assert(f(e()));
        if (l == _n) return _n;
        l += size;
        S sm = e();
        do {
            while (l % 2 == 0) l >>= 1;
            if (!f(op(sm, d[l]))) {
                while (l < size) {
                    l = (2 * l);
                    if (f(op(sm, d[l]))) {
                        sm = op(sm, d[l]);
                        l++;
                    }
                }
                return l - size;
            }
            sm = op(sm, d[l]);
            l++;
        } while ((l & -l) != l);
        return _n;
    }

    template <bool (*f)(S)> int min_left(int r) {//f(op([l,r)))==trueを満たす最小のl
        return min_left(r, [](S x) { return f(x); });
    }
    template <class F> int min_left(int r, F f) {
        assert(0 <= r && r <= _n);
        assert(f(e()));
        if (r == 0) return 0;
        r += size;
        S sm = e();
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!f(op(d[r], sm))) {
                while (r < size) {
                    r = (2 * r + 1);
                    if (f(op(d[r], sm))) {
                        sm = op(d[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(d[r], sm);
        } while ((r & -r) != r);
        return 0;
    }

  private:
    int _n, size, log;
    std::vector<S> d;

    void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }

    int ceil_pow2(int n) {
        int x = 0;
        while ((1U << x) < (unsigned int)(n)) x++;
        return x;
    }
};

template<int mod>
struct ModInt {
    long long x;
    static constexpr int MOD = mod;
 
    ModInt() : x(0) {}
    ModInt(long long y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

    explicit operator int() const {return x;}
 
    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; }
    ModInt operator%(const ModInt &p) const { return ModInt(0); }         
 
    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;
            a -= t * b;
            swap(a, b);
            u -= t * v;
            swap(u, v);
        }
        return ModInt(u);
    }

    ModInt power(long long n) const {
        ModInt ret(1), mul(x);
        while(n > 0) {
            if(n & 1)
            ret *= mul;
            mul *= mul;
            n >>= 1;
        }
        return ret;
    }

    ModInt power(const ModInt p) const{
        return ((ModInt)x).power(p.x);
    }

    friend ostream &operator<<(ostream &os, const ModInt<mod> &p) {
        return os << p.x;
    }
    friend istream &operator>>(istream &is, ModInt<mod> &a) {
        long long x;
        is >> x;
        a = ModInt<mod>(x);
        return (is);
    }
};

using modint = ModInt<mod>;

template<typename T>
struct Compress{
  vector<T> V;
  
  Compress(){
    V.clear();
  }
  Compress(vector<T> &V):V(V){}

  void add(T x){
    V.push_back(x);
  }

  int build(){
    sort(V.begin(),V.end());
    V.erase(unique(V.begin(),V.end()),V.end());
    return  V.size();
  }

  int get(T x){//get the index of the minimum element which is greater than x 
    return lower_bound(V.begin(),V.end(),x)-V.begin();
  }

  pair<int, int> section(T l,T r){//get the range of indexes of [l,r)
    int l_=get(l),r_=get(r);
    return pair<int,int>(l_,r_);
  }

  T &operator [] (int i) {return V[i];};
};


int n;
int a[200010];

modint f(modint a,modint b){return a+b;}
modint e(){return 0;}

void solve(){
  cin >> n;
  Compress<int> comp;
  rep(i,n){
    cin >> a[i];
    comp.add(a[i]);
  }
  int m=comp.build();
  rep(i,n) a[i]=comp.get(a[i]);
  SegmentTree<modint,f,e> seg1_sum(m),seg1_num(m),seg2_sum(m),seg2_num(m);
  modint ans=0;
  per(i,n){
    ans+=seg2_sum.query(0,a[i])+seg2_num.query(0,a[i])*(modint)comp[a[i]];
    seg2_sum.set_val(a[i],seg2_sum.get(a[i])+seg1_sum.query(0,a[i])+seg1_num.query(0,a[i])*(modint)comp[a[i]]);
    seg2_num.set_val(a[i],seg2_num.get(a[i])+seg1_num.query(0,a[i]));
    seg1_sum.set_val(a[i],seg1_sum.get(a[i])+(modint)comp[a[i]]);
    seg1_num.set_val(a[i],seg1_num.get(a[i])+1);
  }
  cout << ans << endl;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(50);
    solve();
}