結果

問題 No.2616 中央番目の中央値
ユーザー pitP
提出日時 2024-01-26 23:37:50
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
TLE  
実行時間 -
コード長 5,484 bytes
コンパイル時間 4,690 ms
コンパイル使用メモリ 267,736 KB
最終ジャッジ日時 2025-02-18 23:49:25
ジャッジサーバーID
（参考情報） 		judge3 / judge5
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 * 21 TLE * 2 -- * 14
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ソースコード

diff #
プレゼンテーションモードにする

// https://judge.yosupo.jp/submission/186019
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
istream &operator>>(istream &is, modint &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint &a) { return os << a.val(); }
istream &operator>>(istream &is, modint998244353 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint998244353 &a) { return os << a.val(); }
istream &operator>>(istream &is, modint1000000007 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint1000000007 &a) { return os << a.val(); } 
typedef long long ll;
typedef vector<vector<int>> Graph;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define FOR(i,l,r) for (int i = l;i < (int)(r); i++)
#define rep(i,n) for (int i = 0;i < (int)(n); i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define my_sort(x) sort(x.begin(), x.end())
#define my_max(x) *max_element(all(x))
#define my_min(x) *min_element(all(x))
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int INF = (1<<30) - 1;
const ll LINF = (1LL<<62) - 1;
const int MOD2 = 1e9+7;
const double PI = acos(-1);
vector<int> di = {1,0,-1,0};
vector<int> dj = {0,1,0,-1};
#ifdef LOCAL
#  include <debug_print.hpp>
#  define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define debug(...) (static_cast<void>(0))
#endif
template <class S, S (*op)(S, S), S (*e)(), class CoordinateType> struct RangeTree {
    using CT = CoordinateType;
    using Point = pair<CT, CT>;
    vector<Point> points;
    vector<vector<Point>> yx;
    vector<atcoder::segtree<S,op,e>> seg;
    int n;
    void _set(int idx, Point p, S val){
        int i = lower_bound(yx[idx].begin(), yx[idx].end(), Point{p.second, p.first}) - yx[idx].begin();
        seg[idx].set(i, val);
    }
    S _prod(int idx, CT yl, CT yr){
        auto comp = [](const Point &lhs, const Point &rhs) {return lhs.first < rhs.first; };
        int il = lower_bound(yx[idx].begin(), yx[idx].end(), Point{yl, yl}, comp) - yx[idx].begin();
        int ir = lower_bound(yx[idx].begin(), yx[idx].end(), Point{yr, yr}, comp) - yx[idx].begin();
        return seg[idx].prod(il, ir);
    }
    void add_point(CT x, CT y){
        points.push_back(Point{x, y});
    }
    void build(){
        sort(points.begin(), points.end());
        points.erase(unique(points.begin(), points.end()), points.end());
        n = points.size();
        yx.resize(2 * n);
        for(int i = 0; i < n; i++) yx[i + n] = { Point{points[i].second, points[i].first}};
        for(int i = n - 1; i > 0; i--){
            auto &lc = yx[2 * i];
            auto &rc = yx[2 * i + 1];
            merge(lc.begin(), lc.end(), rc.begin(), rc.end(), back_inserter(yx[i]));
            yx[i].erase(unique(yx[i].begin(), yx[i].end()), yx[i].end());
        }
        for(const auto &v : yx) seg.emplace_back(v.size());
    }
    void set(CT x, CT y, S val){
        int i = lower_bound(points.begin(), points.end(), Point{x, y}) - points.begin() + n;
        while(i){
            _set(i, Point{x, y}, val);
            i = i >> 1;
        }
    }
    S prod(CT xl, CT xr, CT yl, CT yr){
        auto comp = [](const Point &lhs, const Point &rhs) {return lhs.first < rhs.first; };
        int l = lower_bound(points.begin(), points.end(), Point{xl, yr}, comp) - points.begin() + n;
        int r = lower_bound(points.begin(), points.end(), Point{xr, yr}, comp) - points.begin() + n;
        S sml = e(), smr = e();
        while(l < r){
            if(l & 1) sml = op(sml, _prod(l++, yl, yr));
            if(r & 1) smr = op(_prod(--r, yl, yr), smr);
            l >>= 1;
            r >>= 1;
        }
        return op(sml, smr);
    }
    S get(CT x, CT y){
        return prod(x, x + 1, y, y + 1);
    }
};
using S = int;
S op(S a, S b){
    return a + b;
}
S e(){
    return 0;
}
//https://drken1215.hatenablog.com/entry/2018/06/08/210000
//COMinit()を忘れない!!!
const ll NMAX = 303030;
const ll MOD = 998244353;
//const int MOD = 1e9+7;
ll fac[NMAX],finv[NMAX],inv[NMAX];
void COMinit(){
    fac[0] = fac[1] = 1LL;
    finv[0] = finv[1] = 1LL;
    inv[1] = 1LL;
    for (int i=2;i<NMAX;i++){
        fac[i] = fac[i-1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD/i) % MOD;
        finv[i] = finv[i-1] * inv[i] % MOD;
    }
}
ll nCr(int n,int k){
    if (n<k) return 0LL;
    if (n < 0 || k < 0) return 0LL;
    return fac[n] * (finv[k] * finv[n-k] % MOD) % MOD;
}
ll nPr(int n,int k){
    if (n<k) return 0LL;
    if (n < 0 || k < 0) return 0LL;
    return fac[n] * finv[n-k] % MOD;
}
ll nHr(int n,int r){
    return nCr(n+r-1,r);
}
using mint = modint998244353;
int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    COMinit();
    int N; cin >> N;
    vector<int> P(N);
    rep(i,N) cin >> P[i], P[i]--;
    RangeTree<S,op,e,int> RT;
    rep(i,N) RT.add_point(i, P[i]);
    RT.build();
    rep(i,N) RT.set(i, P[i], 1);
    mint ans = 0;
    for(int c = 0; c < N; c++){
        int lu = RT.prod(0, c, P[c] + 1, N);
        int ld = RT.prod(0, c, 0, P[c]);
        int ru = RT.prod(c, N, P[c] + 1, N);
        int rd = RT.prod(c, N, 0, P[c]);
        ans += nCr(lu + rd, lu) * nCr(ld + ru, ru);
    }
    cout << ans << endl;
}
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