#537486 (C++17) No.1195 数え上げを愛したい（文字列編）

• 問題: No.1195 数え上げを愛したい（文字列編）
• ユーザー: firiexp
• 提出日時: 2020-08-22 14:45:28
• 言語: C++17 (gcc 13.3.0 + boost 1.87.0)
• 結果: CE (最新)
  AC
  (最初)
• 実行時間: -
• コード長: 6,712 bytes
• コンパイル時間: 932 ms
• コンパイル使用メモリ: 91,960 KB
• 最終ジャッジ日時: 2025-01-13 08:53:06
• ジャッジサーバーID （参考情報）: judge5 / judge1

コンパイルメッセージ

main.cpp: In function ‘int main()’:
main.cpp:198:20: error: variable ‘std::array<int, 26> cnt’ has initializer but incomplete type
  198 |     array<int, 26> cnt{};
      |                    ^~~

ソースコード

#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 998244353;
using ll = long long;
using u32 = unsigned;
using u64 = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max()/32*15+208;

constexpr int ntt_mod = 998244353, ntt_root = 3;
template<u32 M = 1000000007>
struct modint{
    u32 val;
    modint(): val(0){}
    template<typename T>
    modint(T t){t %= (T)M; if(t < 0) t += (T)M; val = t;}

    modint pow(ll k) const {
        modint res(1), x(val);
        while(k){
            if(k&1) res *= x;
            x *= x;
            k >>= 1;
        }
        return res;
    }
    template<typename T>
    modint& operator=(T t){t %= (T)M; if(t < 0) t += (T)M; val = t; return *this; }
    modint inv() const {return pow(M-2);}
    modint& operator+=(modint a){ val += a.val; if(val >= M) val -= M; return *this;}
    modint& operator-=(modint a){ if(val < a.val) val += M-a.val; else val -= a.val; return *this;}
    modint& operator*=(modint a){ val = (u64)val*a.val%M; return *this;}
    modint& operator/=(modint a){ return (*this) *= a.inv();}
    modint operator+(modint a) const {return modint(val) +=a;}
    modint operator-(modint a) const {return modint(val) -=a;}
    modint operator*(modint a) const {return modint(val) *=a;}
    modint operator/(modint a) const {return modint(val) /=a;}
    modint operator-(){ return modint(M-val);}
    bool operator==(const modint a) const {return val == a.val;}
    bool operator!=(const modint a) const {return val != a.val;}
    bool operator<(const modint a) const {return val < a.val;}
};

using mint = modint<ntt_mod>;

class NTT {
    static constexpr int max_base = 20, maxN = 1 << max_base; // N <= 524288 * 2
    mint roots[maxN << 1], iroots[maxN << 1];
public:
    NTT() {
        for (int i = 0; i <= max_base; ++i) {
            const int offset = (1 << i) - 1;
            const mint g = mint(ntt_root).pow((ntt_mod)/(1 << i)), ginv = g.inv();
            mint x = 1, y = 1;
            for (int j = 0; j < 1 << i; ++j) {
                roots[offset+j] = x;
                x *= g;
                iroots[offset+j] = y;
                y *= ginv;
            }
        }
    }

    void transform(vector<mint> &a, int sign){
        const int n = a.size();
        if(!sign){ // fft
            for(int k = n >> 1; k >= 1; k >>= 1){
                for (int i = 0; i < n; i += k << 1) {
                    for (int j = 0; j < k; ++j) {
                        const mint tmp = a[i+j]-a[i+j+k];
                        a[i+j] += a[i+j+k];
                        a[i+j+k] = tmp*roots[(k << 1)-1+j];
                    }
                }
            }
        }else { // ifft
            for(int k = 1; k <= (n >> 1); k <<= 1){
                for (int i = 0; i < n; i += k << 1) {
                    for (int j = 0; j < k; ++j) {
                        a[i+j+k] *= iroots[(k << 1)-1+j];
                        const mint tmp = a[i+j]-a[i+j+k];
                        a[i+j] += a[i+j+k];
                        a[i+j+k] = tmp;
                    }
                }
            }
            const mint x = mint(n).inv();
            for (auto &&i : a) i *= x;
        }
    }
};

NTT ntt;

struct poly {
    vector<mint> v;
    poly() = default;
    explicit poly(int n) : v(n) {};
    explicit poly(vector<mint> vv) : v(std::move(vv)) {};
    int size() const {return (int)v.size(); }
    poly cut(int len){
        if(len < v.size()) v.resize(static_cast<unsigned long>(len));
        return *this;
    }
    inline mint& operator[] (int i) {return v[i]; }
    poly& operator+=(const poly &a) {
        this->v.resize(max(size(), a.size()));
        for (int i = 0; i < a.size(); ++i) this->v[i] += a.v[i];
        return *this;
    }
    poly& operator-=(const poly &a) {
        this->v.resize(max(size(), a.size()));
        for (int i = 0; i < a.size(); ++i) this->v[i] -= a.v[i];
        return *this;
    }

    poly& operator*=(poly a) {
        int N = size()+a.size()-1;
        int sz = 1;
        while(sz < N) sz <<= 1;
        this->v.resize(sz); a.v.resize(sz);
        ntt.transform(this->v, 0); ntt.transform(a.v, 0);
        for(int i = 0; i < sz; ++i) this->v[i] *= a.v[i];
        ntt.transform(this->v, 1);
        this->v.resize(N);
        return *this;
    }
    poly& operator/=(const poly &a){ return (*this *= a.inv()); }
    poly operator+(const poly &a) const { return poly(*this) += a; }
    poly operator-(const poly &a) const { return poly(*this) -= a; }
    poly operator*(const poly &a) const { return poly(*this) *= a; }

    poly inv() const {
        int n = size();
        poly r(1);
        r[0] = (this->v[0]).inv();
        int k = 1;
        while(k < n){
            k *= 2;
            poly ff(k);
            for (int i = 0; i < min(k, n); ++i) {
                ff[i] = this->v[i];
            }
            poly nr = (r*r*ff).cut(k);
            for (int i = 0; i < k/2; ++i) {
                nr[i] = (r[i]+r[i]-nr[i]);
                nr[i+k/2] = -nr[i+k/2];
            }
            r = nr;
        }
        r.v.resize(n);
        return r;
    }
};

class Factorial {
    vector<mint> facts, factinv;
public:
    explicit Factorial(int n) : facts(n+1), factinv(n+1) {
        facts[0] = 1;
        for (int i = 1; i < n+1; ++i) facts[i] = facts[i-1] * mint(i);
        factinv[n] = facts[n].inv();
        for (int i = n-1; i >= 0; --i) factinv[i] = factinv[i+1] * mint(i+1);
    }
    mint fact(int k) const {
        if(k >= 0) return facts[k]; else return factinv[-k];
    }
    mint operator[](const int &k) const {
        if(k >= 0) return facts[k]; else return factinv[-k];
    }
    mint C(int p, int q) const {
        if(q < 0 || p < q) return 0;
        return facts[p] * factinv[q] * factinv[p-q];
    }
    mint P(int p, int q) const {
        if(q < 0 || p < q) return 0;
        return facts[p] * factinv[p-q];
    }
    mint H(int p, int q) const {
        if(p < 0 || q < 0) return 0;
        return q == 0 ? 1 : C(p+q-1, q);
    }
};


int main() {
    string s;
    cin >> s;
    array<int, 26> cnt{};
    for (auto &&i : s) {
        cnt[i-'a']++;
    }
    int n = s.size();
    Factorial f(n);
    poly x(1);
    x[0] = 1;
    for (int i = 0; i < 26; ++i) {
        if(cnt[i]){
            poly y(cnt[i]+1);
            for (int j = 0; j <= cnt[i]; ++j) {
                y[j] = f[-j];
            }
            x *= y;
        }
    }
    mint ans = 998244352;
    for (int i = 0; i <= n; ++i) {
        ans += f[i]*x[i];
    }
    cout << ans.val << "\n";
    return 0;
}