#715154 (C++17) No.1740 Alone 'a'

• 問題: No.1740 Alone 'a'
• ユーザー: 👑 emthrm
• 提出日時: 2021-11-12 21:41:31
• 言語: C++17 (gcc 12.3.0 + boost 1.83.0)
• 結果: AC
• 実行時間: 103 ms / 2,000 ms
• コード長: 5,092 bytes
• コンパイル時間: 2,191 ms
• コンパイル使用メモリ: 202,408 KB
• 実行使用メモリ: 5,248 KB
• 最終ジャッジ日時: 2024-11-25 17:37:15
• 合計ジャッジ時間: 4,761 ms
• ジャッジサーバーID （参考情報）: judge4 / judge3

入力	結果	実行時間; 実行使用メモリ
testcase_00	AC	2 ms; 5,248 KB
testcase_01	AC	2 ms; 5,248 KB
testcase_02	AC	2 ms; 5,248 KB
testcase_03	AC	103 ms; 5,248 KB
testcase_04	AC	103 ms; 5,248 KB
testcase_05	AC	6 ms; 5,248 KB
testcase_06	AC	5 ms; 5,248 KB
testcase_07	AC	2 ms; 5,248 KB
testcase_08	AC	2 ms; 5,248 KB
testcase_09	AC	2 ms; 5,248 KB
testcase_10	AC	2 ms; 5,248 KB
testcase_11	AC	20 ms; 5,248 KB
testcase_12	AC	84 ms; 5,248 KB
testcase_13	AC	57 ms; 5,248 KB
testcase_14	AC	98 ms; 5,248 KB
testcase_15	AC	2 ms; 5,248 KB
testcase_16	AC	75 ms; 5,248 KB
testcase_17	AC	3 ms; 5,248 KB
testcase_18	AC	14 ms; 5,248 KB
testcase_19	AC	84 ms; 5,248 KB
testcase_20	AC	44 ms; 5,248 KB
testcase_21	AC	60 ms; 5,248 KB
testcase_22	AC	72 ms; 5,248 KB
testcase_23	AC	72 ms; 5,248 KB
testcase_24	AC	45 ms; 5,248 KB
testcase_25	AC	46 ms; 5,248 KB
testcase_26	AC	59 ms; 5,248 KB
testcase_27	AC	48 ms; 5,248 KB
testcase_28	AC	53 ms; 5,248 KB
testcase_29	AC	98 ms; 5,248 KB
testcase_30	AC	45 ms; 5,248 KB
testcase_31	AC	73 ms; 5,248 KB
testcase_32	AC	54 ms; 5,248 KB
testcase_33	AC	72 ms; 5,248 KB
testcase_34	AC	13 ms; 5,248 KB
testcase_35	AC	51 ms; 5,248 KB
testcase_36	AC	42 ms; 5,248 KB
testcase_37	AC	17 ms; 5,248 KB
testcase_38	AC	36 ms; 5,248 KB
testcase_39	AC	7 ms; 5,248 KB
testcase_40	AC	23 ms; 5,248 KB

ソースコード

#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
constexpr int DY[]{1, 0, -1, 0}, DX[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1}, DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

template <int M>
struct MInt {
  unsigned int val;
  MInt(): val(0) {}
  MInt(long long x) : val(x >= 0 ? x % M : x % M + M) {}
  static constexpr int get_mod() { return M; }
  static void set_mod(int divisor) { assert(divisor == M); }
  static void init(int x = 10000000) { inv(x, true); fact(x); fact_inv(x); }
  static MInt inv(int x, bool init = false) {
    // assert(0 <= x && x < M && std::__gcd(x, M) == 1);
    static std::vector<MInt> inverse{0, 1};
    int prev = inverse.size();
    if (init && x >= prev) {
      // "x!" and "M" must be disjoint.
      inverse.resize(x + 1);
      for (int i = prev; i <= x; ++i) inverse[i] = -inverse[M % i] * (M / i);
    }
    if (x < inverse.size()) return inverse[x];
    unsigned int a = x, b = M; int u = 1, v = 0;
    while (b) {
      unsigned int q = a / b;
      std::swap(a -= q * b, b);
      std::swap(u -= q * v, v);
    }
    return u;
  }
  static MInt fact(int x) {
    static std::vector<MInt> f{1};
    int prev = f.size();
    if (x >= prev) {
      f.resize(x + 1);
      for (int i = prev; i <= x; ++i) f[i] = f[i - 1] * i;
    }
    return f[x];
  }
  static MInt fact_inv(int x) {
    static std::vector<MInt> finv{1};
    int prev = finv.size();
    if (x >= prev) {
      finv.resize(x + 1);
      finv[x] = inv(fact(x).val);
      for (int i = x; i > prev; --i) finv[i - 1] = finv[i] * i;
    }
    return finv[x];
  }
  static MInt nCk(int n, int k) {
    if (n < 0 || n < k || k < 0) return 0;
    if (n - k > k) k = n - k;
    return fact(n) * fact_inv(k) * fact_inv(n - k);
  }
  static MInt nPk(int n, int k) { return n < 0 || n < k || k < 0 ? 0 : fact(n) * fact_inv(n - k); }
  static MInt nHk(int n, int k) { return n < 0 || k < 0 ? 0 : (k == 0 ? 1 : nCk(n + k - 1, k)); }
  static MInt large_nCk(long long n, int k) {
    if (n < 0 || n < k || k < 0) return 0;
    inv(k, true);
    MInt res = 1;
    for (int i = 1; i <= k; ++i) res *= inv(i) * n--;
    return res;
  }
  MInt pow(long long exponent) const {
    MInt tmp = *this, res = 1;
    while (exponent > 0) {
      if (exponent & 1) res *= tmp;
      tmp *= tmp;
      exponent >>= 1;
    }
    return res;
  }
  MInt &operator+=(const MInt &x) { if((val += x.val) >= M) val -= M; return *this; }
  MInt &operator-=(const MInt &x) { if((val += M - x.val) >= M) val -= M; return *this; }
  MInt &operator*=(const MInt &x) { val = static_cast<unsigned long long>(val) * x.val % M; return *this; }
  MInt &operator/=(const MInt &x) { return *this *= inv(x.val); }
  bool operator==(const MInt &x) const { return val == x.val; }
  bool operator!=(const MInt &x) const { return val != x.val; }
  bool operator<(const MInt &x) const { return val < x.val; }
  bool operator<=(const MInt &x) const { return val <= x.val; }
  bool operator>(const MInt &x) const { return val > x.val; }
  bool operator>=(const MInt &x) const { return val >= x.val; }
  MInt &operator++() { if (++val == M) val = 0; return *this; }
  MInt operator++(int) { MInt res = *this; ++*this; return res; }
  MInt &operator--() { val = (val == 0 ? M : val) - 1; return *this; }
  MInt operator--(int) { MInt res = *this; --*this; return res; }
  MInt operator+() const { return *this; }
  MInt operator-() const { return MInt(val ? M - val : 0); }
  MInt operator+(const MInt &x) const { return MInt(*this) += x; }
  MInt operator-(const MInt &x) const { return MInt(*this) -= x; }
  MInt operator*(const MInt &x) const { return MInt(*this) *= x; }
  MInt operator/(const MInt &x) const { return MInt(*this) /= x; }
  friend std::ostream &operator<<(std::ostream &os, const MInt &x) { return os << x.val; }
  friend std::istream &operator>>(std::istream &is, MInt &x) { long long val; is >> val; x = MInt(val); return is; }
};
namespace std { template <int M> MInt<M> abs(const MInt<M> &x) { return x; } }
using ModInt = MInt<MOD>;

int main() {
  int n; string s; cin >> n >> s;
  ModInt dp[2][2]{};
  dp[false][false] = 1;
  for (char c : s) {
    ModInt nx[2][2]{};
    const int v = c - 'a';
    REP(ch, 26) {
      REP(i, 2) REP(j, 2) {
        if ((!i && ch > v) || (j && ch == 0)) continue;
        nx[i || (ch < v)][j || (ch == 0)] += dp[i][j];
      }
    }
    swap(dp, nx);
  }
  cout << dp[true][true] << '\n';
  return 0;
}