結果
問題 | No.2616 中央番目の中央値 |
ユーザー |
|
提出日時 | 2024-01-26 21:51:18 |
言語 | C++14 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 280 ms / 2,000 ms |
コード長 | 4,053 bytes |
コンパイル時間 | 1,911 ms |
コンパイル使用メモリ | 175,832 KB |
実行使用メモリ | 10,864 KB |
最終ジャッジ日時 | 2024-09-28 08:03:10 |
合計ジャッジ時間 | 7,670 ms |
ジャッジサーバーID (参考情報) |
judge3 / judge1 |
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ファイルパターン | 結果 |
---|---|
other | AC * 37 |
ソースコード
#include<bits/stdc++.h>using namespace std;using ll = long long;using pll = pair<ll, ll>;#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)#define rep(i, n) drep(i, 0, n - 1)#define all(a) (a).begin(), (a).end()#define pb push_back#define fi first#define se secondmt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());const ll MOD1000000007 = 1000000007;const ll MOD998244353 = 998244353;const ll MOD[3] = {999727999, 1070777777, 1000000007};const ll LINF = 1LL << 60LL;const int IINF = (1 << 30) - 1;template<typename T, T (*op)(T, T), T (*e)()>struct segtree{int n;vector<T> dat;segtree(int n_){n = 1;while(n < n_) n*=2;dat.resize(2*n, e());}void update(int k, T x){k += n-1;dat[k] = x;while(k > 0){k = (k-1)/2;dat[k] = op(dat[2*k+1], dat[2*k+2]);}}// the prod element of [a, b)T query(int a, int b){return query_sub(a, b, 0, 0, n);}T query_sub(int a, int b, int k, int l, int r){if(r <= a || b <= l){return e();}else if(a <= l && r <= b){return dat[k];}else{T vl = query_sub(a, b, 2*k+1, l, (l+r)/2);T vr = query_sub(a, b, 2*k+2, (l+r)/2, r);return op(vl, vr);}}};template<long long mod>class modint{long long x;public:modint(long long x=0) : x((x%mod+mod)%mod) {}modint operator-() const {return modint(-x);}bool operator==(const modint& a){if(x == a) return true;else return false;}bool operator==(long long a){if(x == a) return true;else return false;}bool operator!=(const modint& a){if(x != a) return true;else return false;}bool operator!=(long long a){if(x != a) return true;else return false;}modint& operator+=(const modint& a) {if ((x += a.x) >= mod) x -= mod;return *this;}modint& operator-=(const modint& a) {if ((x += mod-a.x) >= mod) x -= mod;return *this;}modint& operator*=(const modint& a) {(x *= a.x) %= mod;return *this;}modint operator+(const modint& a) const {modint res(*this);return res+=a;}modint operator-(const modint& a) const {modint res(*this);return res-=a;}modint operator*(const modint& a) const {modint res(*this);return res*=a;}modint pow(long long t) const {if (!t) return 1;modint a = pow(t>>1);a *= a;if (t&1) a *= *this;return a;}// for prime modmodint inv() const {return pow(mod-2);}modint& operator/=(const modint& a) {return (*this) *= a.inv();}modint operator/(const modint& a) const {modint res(*this);return res/=a;}friend std::istream& operator>>(std::istream& is, modint& m) noexcept {is >> m.x;m.x %= mod;if (m.x < 0) m.x += mod;return is;}friend ostream& operator<<(ostream& os, const modint& m){os << m.x;return os;}};using mint = modint<MOD998244353>;int op(int a, int b){return a+b;}int e(){return 0;}void solve(){int n; cin >> n;vector<int> p(n);for(int i=0; i<n; i++){cin >> p[i];p[i]--;}vector<mint> fac(n+1, 1);for(int i=1; i<=n; i++) fac[i] = fac[i-1]*mint(i);segtree<int, op, e> seg(n);mint ans = 0;for(int i=0; i<n; i++){int lx = seg.query(0, p[i]);int ly = i-lx;int rx = p[i]-lx;int ry = n-lx-ly-rx-1;ans += fac[lx+ry]/(fac[lx]*fac[ry])*fac[rx+ly]/(fac[rx]*fac[ly]);seg.update(p[i], 1);}cout << ans << '\n';}int main(){cin.tie(nullptr);ios::sync_with_stdio(false);int T=1;//cin >> T;while(T--) solve();}