#1191240 (C++23) No.3753 Certainly a Cretan

• 問題: No.3753 Certainly a Cretan
• ユーザー: HoyHoyCharhang
• 提出日時: 2026-10-02 23:31:45
• 言語: C++23 (gcc 15.3.0 + boost 1.92.0 + ACL)
• 結果: AC
• 実行時間: 260 ms / 2,500 ms
• コード長: 8,150 bytes
• コンパイル時間: 2,150 ms
• コンパイル使用メモリ: 352,780 KB
• 実行使用メモリ: 35,892 KB
• 最終ジャッジ日時: 2026-10-02 23:32:33
• 合計ジャッジ時間: 7,544 ms
• ジャッジサーバーID （参考情報）: judge2_0 / judge4_0

ファイルパターン	結果
sample	AC * 2
other	AC * 46

ソースコード

#include <bits/stdc++.h>
#define fi first
#define se second
#define rep(i,s,n) for (int i = (s); i < (n); ++i)
#define rrep(i,g,n) for (int i = (n)-1; i >= (g); --i)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define len(x) (int)(x).size()
#define dup(x,y) (((x)+(y)-1)/(y))
#define pb push_back
#define eb emplace_back
#define Field(T) vector<vector<T>>
using namespace std;
using ll = long long;
using ull = unsigned long long;
template<typename T> using pq = priority_queue<T,vector<T>,greater<T>>;
using P = pair<int,int>;
template<class T>bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T&a,T b){if(b<a){a=b;return 1;}return 0;}

template< int mod >
struct ModInt {
  int x;
  ModInt() : x(0) {}
  ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
  ModInt &operator+=(const ModInt &p) {
    if((x += p.x) >= mod) x -= mod;
    return *this;
  }
  ModInt &operator-=(const ModInt &p) {
    if((x += mod - p.x) >= mod) x -= mod;
    return *this;
  }
  ModInt &operator*=(const ModInt &p) {
    x = (int) (1LL * x * p.x % mod);
    return *this;
  }
  ModInt &operator/=(const ModInt &p) {
    *this *= p.inverse();
    return *this;
  }
  ModInt operator-() const { return ModInt(-x); }
  ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
  ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
  ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
  ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
  bool operator==(const ModInt &p) const { return x == p.x; }
  bool operator!=(const ModInt &p) const { return x != p.x; }

  ModInt inverse() const {
    assert(x);
    int a = x, b = mod, u = 1, v = 0, t;
    while(b > 0) {
      t = a / b;
      swap(a -= t * b, b);
      swap(u -= t * v, v);
    }
    return ModInt(u);
  }

  ModInt pow(int64_t n) const {
    ModInt ret(1), mul(x);
    while(n > 0) {
      if(n & 1) ret *= mul;
      mul *= mul;
      n >>= 1;
    }
    return ret;
  }

  friend ostream &operator<<(ostream &os, const ModInt &p) {
    return os << p.x;
  }

  friend istream &operator>>(istream &is, ModInt &a) {
    int64_t t;
    is >> t;
    a = ModInt< mod >(t);
    return (is);
  }

  static int get_mod() { return mod; }
};

template< typename T >
struct Combination {
 private:
  int n_;
  vector<T> fac, inv, finv;
  void extend(int l) {
    while(n_ <= l) {
      fac.emplace_back(fac.back() * T(n_));
      inv.emplace_back(-inv[T::get_mod()%n_] * (T::get_mod()/n_));
      finv.emplace_back(finv.back() * inv[n_]);
      ++n_;
    }
  }
 public:
  Combination() : n_(2), fac({T(1),T(1)}), inv({T(0),T(1)}), finv({T(1),T(1)}) {}
  // n!
  T fact(int n) {
    extend(n);
    return fac[n];
  }
  // (n!)^{-1}
  T ifact(int n) {
    extend(n);
    return finv[n];
  }
  T inverse(int n) {
    extend(n);
    return inv[n];
  }
  // nCk
  T com(int n, int k) {
    if (n < 0 || k < 0 || n < k) return 0;
    extend(n);
    return fac[n] * finv[k] * finv[n-k];
  }
  // nPk
  T perm(int n, int k) {
    if (n < 0 || k < 0 || n < k) return 0;
    extend(n);
    return fac[n] * finv[n-k];
  }
  // nCk を Lucas の定理を用いて計算する。最悪 O(mod) であることに注意。
  T com_lucas(long long n, long long k) {
    if (n < 0 || k < 0 || n < k) return 0;
    T ret = 1;
    const int p = T::get_mod();
    while(n > 0 || k > 0) {
      ret *= com(n % p, k % p);
      n /= p, k /= p;
    }
    return ret;
  }
};

template<class S, S (*op)(S, S), S (*e)()>
struct SegTree {
 public:
  SegTree() : SegTree(0) {}
  SegTree(int n) : SegTree(vector<S>(n, e())) {}
  SegTree(int n, S v) : SegTree(vector<S>(n, v)) {}
  SegTree(const vector<S>& v) : _n(int(v.size())){
    lg = 0;
    while ((1U << lg) < (unsigned int)(_n)) lg++;
    sz = 1 << lg;
    d = vector<S>(2 * sz, e());
    for (int i = 0; i < _n; ++i) d[sz + i] = v[i];
    for (int i = sz-1; i >= 1; --i) {
      update(i);
    }
  }

  void set(int p, S x) {
    assert(0 <= p && p < _n);
    p += sz;
    d[p] = x;
    for (int i = 1; i <= lg; ++i) update(p >> i);
  }

  S get(int p) {
    assert(0 <= p && p < _n);
    return d[p+sz];
  }

  S prod(int l, int r) {
    assert(0 <= l && l <= r && r <= _n);
    S sml = e(), smr = e();
    l += sz, r += sz;
    while(l < r) {
      if (l & 1) sml = op(sml, d[l++]);
      if (r & 1) smr = op(d[--r], smr);
      l >>= 1, r >>= 1;
    }
    return op(sml, smr);
  }

  S all_prod() { return d[1]; }

  using F = function<bool(S)>;

  // max_{r \in [l, n]} f(prod(l, r)) == true
  int max_right(int l, const F &f) {
    assert(0 <= l && l <= _n);
    assert(f(e()));
    if (l == _n) return _n;
    l += sz;
    S v = e();
    do {
      while(l % 2 == 0) l >>= 1;
      if (!f(op(v, d[l]))) {
        while(l < sz) {
          l *= 2;
          if (f(op(v, d[l]))) {
            v = op(v, d[l]);
            ++l;
          }
        }
        return l - sz;
      }
      v = op(v, d[l]);
      ++l;
    } while((l & -l) != l);
    return _n;
  }

  // min_{l \in [0, r]} f(prod(l, r)) == true
  int min_left(int r, const F &f) {
    assert(0 <= r && r <= _n);
    assert(f(e()));
    if (r == 0) return 0;
    r += sz;
    S v = e();
    do {
      --r;
      while(r > 0 && (r % 2)) r >>= 1;
      if (!f(op(d[r], v))) {
        while(r < sz) {
          r = r*2+1;
          if (f(op(d[r], v))) {
            v = op(d[r], v);
            --r;
          }
        }
        return r+1-sz;
      }
      v = op(d[r], v);
    } while((r & -r) != r);
    return 0;
  }

 private:
  int _n, sz, lg;
  vector<S> d;

  void update(int k) {d[k] = op(d[2*k], d[2*k+1]);}
};

using mint = ModInt<998244353>;

mint op(mint a, mint b) { return a*b; }
mint e() { return 1; }

int main() {
  Combination<mint> com;
  int n, q; string s;
  cin >> n >> q >> s;
  SegTree<mint,op,e> seg(n);
  set<int> st;
  st.emplace(0);
  rep(i,0,n-1) {
    if (s[i] != s[i+1]) {
      st.emplace(i+1);
    }
  }
  function<mint(int)> f = [&](int n) {
    if (n%2 == 1) return mint(0);
    return com.com(n, n/2)*com.inverse((n/2)+1);
  };
  auto itr = st.begin();
  while(next(itr) != st.end()) {
    int x = *next(itr);
    seg.set(x, f(x-*(itr)));
    itr = next(itr);
  }
  while(q--) {
    int t;
    cin >> t;
    if (t == 1) {
      int i;
      cin >> i;
      --i;
      if (i > 0 && s[i-1] != s[i]) {
        seg.set(i, 1);
        st.erase(i);
        auto itr = st.lower_bound(i);
        if (itr != st.end()) {
          seg.set(*itr, f((*itr)-(*prev(itr))));
        }
      }
      if (i+1 < n && s[i] != s[i+1]) {
        seg.set(i+1, 1);
        st.erase(i+1);
        auto itr = st.lower_bound(i+1);
        if (itr != st.end()) {
          seg.set(*itr, f((*itr)-(*prev(itr))));
        }
      }
      s[i] = (s[i] == 'Y' ? 'N' : 'Y');
      if (i > 0 && s[i-1] != s[i]) {
        st.emplace(i);
        auto itr = st.lower_bound(i);
        if (itr != st.begin()) {
          seg.set(*itr, f((*itr)-(*prev(itr))));
        } else {
          seg.set(*itr, f(*itr));
        }
        if (next(itr) != st.end()) {
          seg.set(*next(itr), f((*next(itr))-(*itr)));
        }
      }
      if (i+1 < n && s[i] != s[i+1]) {
        st.emplace(i+1);
        auto itr = st.lower_bound(i+1);
        if (itr != st.begin()) {
          seg.set(*itr, f((*itr)-(*prev(itr))));
        } else {
          seg.set(*itr, f(*itr));
        }
        if (next(itr) != st.end()) {
          seg.set(*next(itr), f((*next(itr))-(*itr)));
        }
      }
    } else {
      int k;
      cin >> k;
      mint ans = seg.all_prod();
      // cout << ans << endl;
      int c = n-(st.empty() ? 0 : *(prev(st.end())));
      // cout << "c = " << c << endl;
      k -= (n-c)/2;
      if (k < 0) {
        cout << 0 << endl;
        continue;
      }
      if (s.back() == 'Y') k = c-k;
      if (k-(c-k) < 0) {
        cout << 0 << endl;
        continue;
      }
      ans *= (com.com(c,k)-com.com(c,k+1));
      cout << ans << endl;
    }
    // cout << s << endl;
    // rep(i,0,n) cout << seg.get(i) << " ";
    // cout << endl;
  }
  return 0;
}