結果

問題 No.2616 中央番目の中央値
ユーザー siganaisiganai
提出日時 2024-01-26 21:35:56
言語 C++17(gcc12)
(gcc 12.3.0 + boost 1.87.0)
結果
AC  
実行時間 180 ms / 2,000 ms
コード長 10,484 bytes
コンパイル時間 2,669 ms
コンパイル使用メモリ 209,212 KB
実行使用メモリ 12,080 KB
最終ジャッジ日時 2024-09-28 07:50:08
合計ジャッジ時間 6,893 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
other AC * 37
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 # 

#line 1 "main.cpp"
//#pragma GCC target("avx,avx2")
//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
#ifdef LOCAL
#include <debug.hpp>
#define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (static_cast<void>(0))
#endif
using namespace std;
using ll = long long;
using ld = long double;
using pll = pair<ll, ll>;
using pii = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vpii = vector<pii>;
using vpll = vector<pll>;
using vs = vector<string>;
template<class T> using pq = priority_queue<T, vector<T>, greater<T>>;
#define overload4(_1, _2, _3, _4, name, ...) name
#define overload3(a,b,c,name,...) name
#define rep1(n) for (ll UNUSED_NUMBER = 0; UNUSED_NUMBER < (n); ++UNUSED_NUMBER)
#define rep2(i, n) for (ll i = 0; i < (n); ++i)
#define rep3(i, a, b) for (ll i = (a); i < (b); ++i)
#define rep4(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
#define rrep1(n) for(ll i = (n) - 1;i >= 0;i--)
#define rrep2(i,n) for(ll i = (n) - 1;i >= 0;i--)
#define rrep3(i,a,b) for(ll i = (b) - 1;i >= (a);i--)
#define rrep4(i,a,b,c) for(ll i = (a) + ((b)-(a)-1) / (c) * (c);i >= (a);i -= c)
#define rrep(...) overload4(__VA_ARGS__, rrep4, rrep3, rrep2, rrep1)(__VA_ARGS__)
#define all1(i) begin(i) , end(i)
#define all2(i,a) begin(i) , begin(i) + a
#define all3(i,a,b) begin(i) + a , begin(i) + b
#define all(...) overload3(__VA_ARGS__, all3, all2, all1)(__VA_ARGS__)
#define sum(...) accumulate(all(__VA_ARGS__),0LL)
template<class T> bool chmin(T &a, const T &b){ if(a > b){ a = b; return 1; } else return 0; }
template<class T> bool chmax(T &a, const T &b){ if(a < b){ a = b; return 1; } else return 0; }
template<class T> auto min(const T& a){return *min_element(all(a));}
template<class T> auto max(const T& a){return *max_element(all(a));}
template<class... Ts> void in(Ts&... t);
#define INT(...) int __VA_ARGS__; in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__; in(__VA_ARGS__)
#define STR(...) string __VA_ARGS__; in(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__; in(__VA_ARGS__)
#define DBL(...) double __VA_ARGS__; in(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__; in(__VA_ARGS__)
#define VEC(type, name, size) vector<type> name(size); in(name)
#define VV(type, name, h, w) vector<vector<type>> name(h, vector<type>(w)); in(name)
ll intpow(ll a, ll b){ ll ans = 1; while(b){if(b & 1) ans *= a; a *= a; b /= 2;} return ans;}
ll modpow(ll a, ll b, ll p){ ll ans = 1; a %= p;if(a < 0) a += p;while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; }
void Yes() {cout << "Yes\n";return;}
void No() {cout << "No\n";return;}
void YES() {cout << "YES\n";return;}
void NO() {cout << "NO\n";return;}
void First() {cout << "First\n";return;}
void Second() {cout << "Second\n";return;}
namespace IO{
#define VOID(a) decltype(void(a))
struct setting{ setting(){cin.tie(nullptr); ios::sync_with_stdio(false);fixed(cout); cout.precision(12);}} setting;
template<int I> struct P : P<I-1>{};
template<> struct P<0>{};
template<class T> void i(T& t){ i(t, P<3>{}); }
void i(vector<bool>::reference t, P<3>){ int a; i(a); t = a; }
template<class T> auto i(T& t, P<2>) -> VOID(cin >> t){ cin >> t; }
template<class T> auto i(T& t, P<1>) -> VOID(begin(t)){ for(auto&& x : t) i(x); }
template<class T, size_t... idx> void ituple(T& t, index_sequence<idx...>){in(get<idx>(t)...);}
template<class T> auto i(T& t, P<0>) -> VOID(tuple_size<T>{}){ituple(t, make_index_sequence<tuple_size<T>::value>{});} 
#undef VOID
}
#define unpack(a) (void)initializer_list<int>{(a, 0)...}
template<class... Ts> void in(Ts&... t){ unpack(IO :: i(t)); }

#undef unpack
static const double PI = 3.1415926535897932;
template <class F> struct REC {
    F f;
    REC(F &&f_) : f(forward<F>(f_)) {}
    template <class... Args> auto operator()(Args &&...args) const { return f(*this, forward<Args>(args)...); }};

constexpr int mod = 998244353;
//constexpr int mod = 1000000007;
#line 2 "library/modint/Modint.hpp"
template <int mod>
struct Modint{
    int x;
    Modint():x(0) {}
    Modint(long long 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;}
    Modint &operator ++() {if(x == mod - 1) x = 0; else x++; return *this;}
    Modint &operator --() {if(x == 0) x = mod - 1; else x--; return *this;} 
    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(long long n) const {
        Modint ret(1), mul(x);
        while (n > 0) {
            if (n & 1) ret *= mul;
            mul *= mul;
            n >>= 1;
        }
        return ret;}
    friend ostream &operator<<(ostream &os, const Modint &p) { return os << p.x; }
    friend istream &operator>>(istream &is, Modint &a) {
        long long t;
        is >> t;
        a = Modint<mod>(t);
        return (is);
    }
    int get() const { return x; }
    static constexpr int get_mod() {return mod;}
};
#line 90 "main.cpp"
using mint = Modint<mod>;
using vm = vector<mint>;
using vvm = vector<vm>;
using vvvm = vector<vvm>;
#line 2 "library/segtree/segtree.hpp"
template <typename T, typename OP>
struct segtree {
    int N;
    int size;
    vector<T> seg;
    const OP op;
    const T I;
    segtree(OP _op, const T &I_) : N(0), size(0), op(_op), I(I_) {}
    segtree(int _N, OP _op, const T &I_) : op(_op), I(I_) { init(_N); }
    segtree(const vector<T> &v, OP _op, T I_) : op(_op), I(I_) {
        init(v.size());
        for (int i = 0; i < (int)v.size(); i++) {
            seg[i + size] = v[i];
        }
        build();
    }
    void init(int _N) {
        N = _N;
        size = 1;
        while (size < N) size <<= 1;
        seg.assign(2 * size, I);
    }
    void build() {
        for (int k = size - 1; k > 0; k--) {
            seg[k] = op(seg[2 * k], seg[2 * k + 1]);
        }
    }
    void set(int p, T x) {
        assert(0 <= p && p < N);
        p += size;
        seg[p] = x;
        while (p >>= 1) {
            seg[p] = op(seg[2 * p], seg[2 * p + 1]);
        }
    }
    void add(int p, T x) {
        assert(0 <= p && p < N);
        p += size;
        seg[p] += x;
        while (p >>= 1) {
            seg[p] = op(seg[2 * p], seg[2 * p + 1]);
        }
    }
    T get(int p) const {
        assert(0 <= p && p < N);
        return seg[p + size];
    }
    // query to [l, r)
    T prod(int l, int r) {
        assert(0 <= l && l <= r && r <= N);
        T L = I, R = I;
        for (l += size, r += size; l < r; l >>= 1, r >>= 1) {
            if (l & 1) L = op(L, seg[l++]);
            if (r & 1) R = op(seg[--r], R);
        }
        return op(L, R);
    }
    T all_prod() {return seg[1];}
    // check(a[l] * ...  * a[r-1]) が true となる最大の r
    // (右端まですべて true なら N を返す)
    template <class C>
    int max_right(int l, C check) {
        assert(0 <= l && l <= N);
        assert(check(I) == true);
        if (l == N) return N;
        l += size;
        T sm = I;
        do {
            while (l % 2 == 0) l >>= 1;
            if (!check(op(sm, seg[l]))) {
                while (l < size) {
                    l = (2 * l);
                    if (check(op(sm, seg[l]))) {
                        sm = op(sm, seg[l]);
                        l++;
                    }
                }
                return l - size;
            }
            sm = op(sm, seg[l]);
            l++;
        } while ((l & -l) != l);
        return N;
    }
    // check(a[l] * ... * a[r-1]) が true となる最小の l
    // (左端まで true なら 0 を返す)
    template <typename C>
    int min_left(int r, C check) {
        assert(0 <= r && r <= N);
        assert(check(I) == true);
        if (r == 0) return 0;
        r += size;
        T sm = I;
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!check(op(seg[r], sm))) {
                while (r < size) {
                    r = (2 * r + 1);
                    if (check(op(seg[r], sm))) {
                        sm = op(seg[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(seg[r], sm);
        } while ((r & -r) != r);
        return 0;
    }
};
#line 95 "main.cpp"
using T = int;
T op(T x,T y) {return x + y;}
T e() {return 0;}
vector<mint> fact, fact_inv;
void make_fact(int n){
    fact.resize(n+1), fact_inv.resize(n+1);
    fact[0] = mint(1); rep(i,1,n+1) fact[i] = fact[i-1] * mint(i);
    fact_inv[n] = fact[n].inverse(); rrep(i,0,n) fact_inv[i] = fact_inv[i+1] * mint(i+1);
}
mint ncr(int n, int r){ if(n < 0 || r < 0 || n < r) return mint(0); return fact[n] * fact_inv[r] * fact_inv[n-r];}
mint npr(int n, int r){ if(n < 0 || r < 0 || n < r) return mint(0); return fact[n] * fact_inv[n-r]; }
void solve() {
    INT(n);
    VEC(int,p,n);
    vi inv(n);
    make_fact(n);
    rep(i,n) inv[p[i] - 1] = i;
    segtree<int,decltype(&op)> seg(n,op,e());
    mint ans;
    rep(i,n) {
        int c1 = seg.prod(0,inv[i]);
        int c2 = inv[i] - c1;
        int c3 = seg.prod(inv[i]+1,n);
        int c4 = n - 1 - c1 - c2 - c3;
        ans += ncr(c1+c4,c1) * ncr(c2+c3,c2);
        seg.add(inv[i],1);
    }
    cout << ans << '\n';
}
int main() {
	//INT(TT);
	int TT = 1;
	while(TT--) solve();
}
0