結果

問題 No.1193 Penguin Sequence
ユーザー 👑 hitonanodehitonanode
提出日時 2020-08-22 13:56:37
言語 C++17
(gcc 13.2.0 + boost 1.83.0)
結果
AC  
実行時間 230 ms / 2,000 ms
コード長 10,087 bytes
コンパイル時間 2,573 ms
コンパイル使用メモリ 212,384 KB
実行使用メモリ 6,420 KB
最終ジャッジ日時 2023-08-05 11:06:47
合計ジャッジ時間 10,846 ms
ジャッジサーバーID
（参考情報） 		judge13 / judge12
このコードへのチャレンジ（β）

テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 196 ms
6,112 KB
testcase_01 AC 228 ms
6,212 KB
testcase_02 AC 227 ms
6,196 KB
testcase_03 AC 228 ms
6,248 KB
testcase_04 AC 230 ms
6,164 KB
testcase_05 AC 228 ms
6,140 KB
testcase_06 AC 227 ms
6,112 KB
testcase_07 AC 230 ms
6,116 KB
testcase_08 AC 227 ms
6,188 KB
testcase_09 AC 228 ms
6,340 KB
testcase_10 AC 230 ms
6,168 KB
testcase_11 AC 129 ms
4,836 KB
testcase_12 AC 129 ms
4,888 KB
testcase_13 AC 196 ms
5,772 KB
testcase_14 AC 182 ms
5,720 KB
testcase_15 AC 214 ms
6,088 KB
testcase_16 AC 191 ms
6,420 KB
testcase_17 AC 1 ms
4,380 KB
testcase_18 AC 19 ms
4,380 KB
testcase_19 AC 223 ms
6,096 KB
testcase_20 AC 178 ms
5,800 KB
testcase_21 AC 143 ms
4,976 KB
testcase_22 AC 24 ms
4,376 KB
testcase_23 AC 118 ms
4,684 KB
testcase_24 AC 103 ms
4,532 KB
testcase_25 AC 48 ms
4,380 KB
testcase_26 AC 13 ms
4,380 KB
testcase_27 AC 190 ms
5,864 KB
testcase_28 AC 134 ms
4,908 KB
testcase_29 AC 194 ms
5,888 KB
testcase_30 AC 67 ms
4,380 KB
testcase_31 AC 56 ms
4,376 KB
testcase_32 AC 152 ms
5,180 KB
testcase_33 AC 107 ms
4,664 KB
testcase_34 AC 87 ms
4,408 KB
testcase_35 AC 109 ms
4,516 KB
testcase_36 AC 84 ms
4,376 KB
testcase_37 AC 185 ms
5,656 KB
testcase_38 AC 2 ms
4,376 KB
testcase_39 AC 2 ms
4,376 KB
testcase_40 AC 1 ms
4,376 KB
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 # 

#include <bits/stdc++.h>
using namespace std;
using lint = long long;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template <typename T> void ndarray(vector<T> &vec, int len) { vec.resize(len); }
template <typename T, typename... Args> void ndarray(vector<T> &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); }
template <typename V, typename T> void ndfill(V &x, const T &val) { x = val; }
template <typename V, typename T> void ndfill(vector<V> &vec, const T &val) { for (auto &v : vec) ndfill(v, val); }
template <typename T> bool chmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template <typename T> bool chmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; }
template <typename T1, typename T2> pair<T1, T2> operator+(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first + r.first, l.second + r.second); }
template <typename T1, typename T2> pair<T1, T2> operator-(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first - r.first, l.second - r.second); }
template <typename T> vector<T> srtunq(vector<T> vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); return vec; }
template <typename T> istream &operator>>(istream &is, vector<T> &vec) { for (auto &v : vec) is >> v; return is; }
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) { os << '['; for (auto v : vec) os << v << ','; os << ']'; return os; }
#if __cplusplus >= 201703L
template <typename... T> istream &operator>>(istream &is, tuple<T...> &tpl) { std::apply([&is](auto &&... args) { ((is >> args), ...);}, tpl); return is; }
template <typename... T> ostream &operator<<(ostream &os, const tuple<T...> &tpl) { std::apply([&os](auto &&... args) { ((os << args << ','), ...);}, tpl); return os; }
#endif
template <typename T> ostream &operator<<(ostream &os, const deque<T> &vec) { os << "deq["; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <typename T> ostream &operator<<(ostream &os, const set<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T> ostream &operator<<(ostream &os, const unordered_set<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa) { os << '(' << pa.first << ',' << pa.second << ')'; return os; }
template <typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
template <typename TK, typename TV> ostream &operator<<(ostream &os, const unordered_map<TK, TV> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
#ifdef HITONANODE_LOCAL
#define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl
#else
#define dbg(x)
#endif

template <int mod>
struct ModInt
{
    using lint = long long;
    static int get_mod() { return mod; }
    static int get_primitive_root() {
        static int primitive_root = 0;
        if (!primitive_root) {
            primitive_root = [&](){
                std::set<int> fac;
                int v = mod - 1;
                for (lint i = 2; i * i <= v; i++) while (v % i == 0) fac.insert(i), v /= i;
                if (v > 1) fac.insert(v);
                for (int g = 1; g < mod; g++) {
                    bool ok = true;
                    for (auto i : fac) if (ModInt(g).power((mod - 1) / i) == 1) { ok = false; break; }
                    if (ok) return g;
                }
                return -1;
            }();
        }
        return primitive_root;
    }
    int val;
    constexpr ModInt() : val(0) {}
    constexpr ModInt &_setval(lint v) { val = (v >= mod ? v - mod : v); return *this; }
    constexpr ModInt(lint v) { _setval(v % mod + mod); }
    explicit operator bool() const { return val != 0; }
    constexpr ModInt operator+(const ModInt &x) const { return ModInt()._setval((lint)val + x.val); }
    constexpr ModInt operator-(const ModInt &x) const { return ModInt()._setval((lint)val - x.val + mod); }
    constexpr ModInt operator*(const ModInt &x) const { return ModInt()._setval((lint)val * x.val % mod); }
    constexpr ModInt operator/(const ModInt &x) const { return ModInt()._setval((lint)val * x.inv() % mod); }
    constexpr ModInt operator-() const { return ModInt()._setval(mod - val); }
    constexpr ModInt &operator+=(const ModInt &x) { return *this = *this + x; }
    constexpr ModInt &operator-=(const ModInt &x) { return *this = *this - x; }
    constexpr ModInt &operator*=(const ModInt &x) { return *this = *this * x; }
    constexpr ModInt &operator/=(const ModInt &x) { return *this = *this / x; }
    friend constexpr ModInt operator+(lint a, const ModInt &x) { return ModInt()._setval(a % mod + x.val); }
    friend constexpr ModInt operator-(lint a, const ModInt &x) { return ModInt()._setval(a % mod - x.val + mod); }
    friend constexpr ModInt operator*(lint a, const ModInt &x) { return ModInt()._setval(a % mod * x.val % mod); }
    friend constexpr ModInt operator/(lint a, const ModInt &x) { return ModInt()._setval(a % mod * x.inv() % mod); }
    constexpr bool operator==(const ModInt &x) const { return val == x.val; }
    constexpr bool operator!=(const ModInt &x) const { return val != x.val; }
    bool operator<(const ModInt &x) const { return val < x.val; }  // To use std::map<ModInt, T>
    friend std::istream &operator>>(std::istream &is, ModInt &x) { lint t; is >> t; x = ModInt(t); return is; }
    friend std::ostream &operator<<(std::ostream &os, const ModInt &x) { os << x.val;  return os; }
    constexpr lint power(lint n) const {
        lint ans = 1, tmp = this->val;
        while (n) {
            if (n & 1) ans = ans * tmp % mod;
            tmp = tmp * tmp % mod;
            n /= 2;
        }
        return ans;
    }
    constexpr lint inv() const { return this->power(mod - 2); }
    constexpr ModInt operator^(lint n) const { return ModInt(this->power(n)); }
    constexpr ModInt &operator^=(lint n) { return *this = *this ^ n; }

    inline ModInt fac() const {
        static std::vector<ModInt> facs;
        int l0 = facs.size();
        if (l0 > this->val) return facs[this->val];

        facs.resize(this->val + 1);
        for (int i = l0; i <= this->val; i++) facs[i] = (i == 0 ? ModInt(1) : facs[i - 1] * ModInt(i));
        return facs[this->val];
    }

    ModInt doublefac() const {
        lint k = (this->val + 1) / 2;
        if (this->val & 1) return ModInt(k * 2).fac() / ModInt(2).power(k) / ModInt(k).fac();
        else return ModInt(k).fac() * ModInt(2).power(k);
    }

    ModInt nCr(const ModInt &r) const {
        if (this->val < r.val) return ModInt(0);
        return this->fac() / ((*this - r).fac() * r.fac());
    }

    ModInt sqrt() const {
        if (val == 0) return 0;
        if (mod == 2) return val;
        if (power((mod - 1) / 2) != 1) return 0;
        ModInt b = 1;
        while (b.power((mod - 1) / 2) == 1) b += 1;
        int e = 0, m = mod - 1;
        while (m % 2 == 0) m >>= 1, e++;
        ModInt x = power((m - 1) / 2), y = (*this) * x * x;
        x *= (*this);
        ModInt z = b.power(m);
        while (y != 1) {
            int j = 0;
            ModInt t = y;
            while (t != 1) j++, t *= t;
            z = z.power(1LL << (e - j - 1));
            x *= z, z *= z, y *= z;
            e = j;
        }
        return ModInt(std::min(x.val, mod - x.val));
    }
};
constexpr lint MOD = 998244353;
using mint = ModInt<MOD>;

// 1-indexed BIT (i : [1, len])
template <typename T>
struct BIT : std::vector<T>
{
    BIT(int len = 0) : std::vector<T>(len + 1) {}
    void reset() { fill(this->begin(), this->end(), 0); }
    void add(int pos, T v) {
        while (pos > 0 and pos < (int)this->size()) (*this)[pos] += v, pos += pos & -pos;
    }
    T sum(int pos) const { // (0, pos]
        T res = 0;
        while (pos > 0) res += (*this)[pos], pos -= pos & -pos;
        return res;
    }
    friend std::ostream &operator<<(std::ostream &os, const BIT &bit) {
        T prv = 0;
        os << '[';
        for (int i = 1; i < (int)bit.size(); i++) {
            T now = bit.sum(i);
            os << now - prv << ",";
            prv = now;
        }
        os << ']';
        return os;
    }
};
mint InvNb(vector<int> vec)
{
    int N = vec.size();
    BIT<int> bit(N);
    mint ret = 0;
    for (auto v : vec)
    {
        ret += bit.sum(N) - bit.sum(v + 1);
        bit.add(v + 1, 1);
    }
    return ret;
}

int main()
{
    int N;
    cin >> N;
    vector<int> A(N);
    cin >> A;
    auto AA = srtunq(A);
    for (auto &a : A) a = lower_bound(ALL(AA), a) - AA.begin();

    mint i1 = InvNb(A);
    reverse(ALL(A));
    mint i2 = InvNb(A);

    mint pij = 0, pji = 0;
    mint ei = 0;

    mint ninv = mint(1) / N;
    REP(i, N)
    {
        pji += ei * (i + 1) * ninv;
        pij += ei * (i + 1) * ninv;
        if (i > 0) pij += mint(N - 2).nCr(i + 1 - 2) / mint(N).nCr(i + 1);
        ei += mint(i + 1) * ninv;
    }
    mint f = 1;
    REP(i, N) f *= mint(N).nCr(i + 1);
    dbg(ei);
    dbg(f);
    dbg(i1);
    dbg(i2);
    cout << f * (i1 * pij + i2 * pji) << '\n';
}
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