結果

問題 No.2794 I Love EDPC-T
ユーザー 👑 hos.lyrichos.lyric
提出日時 2024-06-21 22:08:39
言語 C++14
(gcc 12.3.0 + boost 1.83.0)
結果
RE  
実行時間 -
コード長 5,676 bytes
コンパイル時間 1,115 ms
コンパイル使用メモリ 111,960 KB
実行使用メモリ 79,316 KB
最終ジャッジ日時 2024-06-21 22:08:55
合計ジャッジ時間 14,818 ms
ジャッジサーバーID
(参考情報)
judge5 / judge4
このコードへのチャレンジ
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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 7 ms
9,280 KB
testcase_01 AC 8 ms
9,408 KB
testcase_02 AC 7 ms
10,796 KB
testcase_03 AC 7 ms
8,772 KB
testcase_04 AC 7 ms
9,028 KB
testcase_05 AC 7 ms
8,900 KB
testcase_06 AC 488 ms
41,132 KB
testcase_07 AC 1,136 ms
50,764 KB
testcase_08 AC 2,078 ms
61,008 KB
testcase_09 AC 8 ms
8,904 KB
testcase_10 AC 8 ms
8,392 KB
testcase_11 AC 8 ms
9,288 KB
testcase_12 AC 7 ms
9,156 KB
testcase_13 RE -
testcase_14 RE -
testcase_15 RE -
testcase_16 RE -
testcase_17 RE -
testcase_18 RE -
testcase_19 RE -
testcase_20 RE -
testcase_21 RE -
testcase_22 RE -
testcase_23 RE -
testcase_24 RE -
testcase_25 RE -
testcase_26 AC 10 ms
9,468 KB
testcase_27 AC 8 ms
8,776 KB
testcase_28 RE -
testcase_29 RE -
testcase_30 RE -
testcase_31 RE -
testcase_32 RE -
testcase_33 RE -
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 <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")

////////////////////////////////////////////////////////////////////////////////
template <unsigned M_> struct ModInt {
  static constexpr unsigned M = M_;
  unsigned x;
  constexpr ModInt() : x(0U) {}
  constexpr ModInt(unsigned x_) : x(x_ % M) {}
  constexpr ModInt(unsigned long long x_) : x(x_ % M) {}
  constexpr ModInt(int x_) : x(((x_ %= static_cast<int>(M)) < 0) ? (x_ + static_cast<int>(M)) : x_) {}
  constexpr ModInt(long long x_) : x(((x_ %= static_cast<long long>(M)) < 0) ? (x_ + static_cast<long long>(M)) : x_) {}
  ModInt &operator+=(const ModInt &a) { x = ((x += a.x) >= M) ? (x - M) : x; return *this; }
  ModInt &operator-=(const ModInt &a) { x = ((x -= a.x) >= M) ? (x + M) : x; return *this; }
  ModInt &operator*=(const ModInt &a) { x = (static_cast<unsigned long long>(x) * a.x) % M; return *this; }
  ModInt &operator/=(const ModInt &a) { return (*this *= a.inv()); }
  ModInt pow(long long e) const {
    if (e < 0) return inv().pow(-e);
    ModInt a = *this, b = 1U; for (; e; e >>= 1) { if (e & 1) b *= a; a *= a; } return b;
  }
  ModInt inv() const {
    unsigned a = M, b = x; int y = 0, z = 1;
    for (; b; ) { const unsigned q = a / b; const unsigned c = a - q * b; a = b; b = c; const int w = y - static_cast<int>(q) * z; y = z; z = w; }
    assert(a == 1U); return ModInt(y);
  }
  ModInt operator+() const { return *this; }
  ModInt operator-() const { ModInt a; a.x = x ? (M - x) : 0U; return a; }
  ModInt operator+(const ModInt &a) const { return (ModInt(*this) += a); }
  ModInt operator-(const ModInt &a) const { return (ModInt(*this) -= a); }
  ModInt operator*(const ModInt &a) const { return (ModInt(*this) *= a); }
  ModInt operator/(const ModInt &a) const { return (ModInt(*this) /= a); }
  template <class T> friend ModInt operator+(T a, const ModInt &b) { return (ModInt(a) += b); }
  template <class T> friend ModInt operator-(T a, const ModInt &b) { return (ModInt(a) -= b); }
  template <class T> friend ModInt operator*(T a, const ModInt &b) { return (ModInt(a) *= b); }
  template <class T> friend ModInt operator/(T a, const ModInt &b) { return (ModInt(a) /= b); }
  explicit operator bool() const { return x; }
  bool operator==(const ModInt &a) const { return (x == a.x); }
  bool operator!=(const ModInt &a) const { return (x != a.x); }
  friend std::ostream &operator<<(std::ostream &os, const ModInt &a) { return os << a.x; }
};
////////////////////////////////////////////////////////////////////////////////

constexpr unsigned MO = 998244353;
using Mint = ModInt<MO>;

constexpr int LIM_INV = 400'010;
Mint inv[LIM_INV], fac[LIM_INV], invFac[LIM_INV];

void prepare() {
  inv[1] = 1;
  for (int i = 2; i < LIM_INV; ++i) {
    inv[i] = -((Mint::M / i) * inv[Mint::M % i]);
  }
  fac[0] = invFac[0] = 1;
  for (int i = 1; i < LIM_INV; ++i) {
    fac[i] = fac[i - 1] * i;
    invFac[i] = invFac[i - 1] * inv[i];
  }
}
Mint binom(Int n, Int k) {
  if (n < 0) {
    if (k >= 0) {
      return ((k & 1) ? -1 : +1) * binom(-n + k - 1, k);
    } else if (n - k >= 0) {
      return (((n - k) & 1) ? -1 : +1) * binom(-k - 1, n - k);
    } else {
      return 0;
    }
  } else {
    if (0 <= k && k <= n) {
      assert(n < LIM_INV);
      return fac[n] * invFac[k] * invFac[n - k];
    } else {
      return 0;
    }
  }
}


int N;
char S[200'010];

Mint slow() {
  if (~string(S).find("<<")) return 0;
  if (string(S) == string(N - 1, '>')) return 0;
  static Mint dp[3010][2][3010];
  for (int i = 0; i < N; ++i) for (int u = 0; u < 2; ++u) for (int x = 0; x < N; ++x) {
    dp[i][u][x] = 0;
  }
  for (int x = 0; x < N; ++x) {
    dp[0][1][x] = 1;
  }
  for (int i = 0; i < N - 1; ++i) {
    for (int u = 0; u < 2; ++u) {
      // not prefix min
      if (!(i < N - 2 && S[i + 1] == '<') && !(u && S[i] == '>')) {
        for (int x = 0; x < N; ++x) {
          dp[i + 1][0][x] += dp[i][u][x];
        }
      }
      // prefix min
      if (S[i] == '>') {
        for (int x = 0; x <= N - (i+1); ++x) {
          for (int y = 0; y < x; ++y) {
            dp[i + 1][1][y] += dp[i][u][x];
          }
        }
      }
    }
  }
// if(N<=4){for(int i=0;i<N;++i)for(int u=0;u<2;++u){cerr<<"dp["<<i<<"]["<<u<<"] = ";pv(dp[i][u],dp[i][u]+N);}}
  Mint ans = 0;
  for (int u = 0; u < 2; ++u) {
    ans += dp[N - 1][u][0];
  }
  return ans;
}

int main() {
  prepare();
  for (; ~scanf("%d", &N); ) {
    scanf("%s", S);
    const Mint ans = slow();
    printf("%u\n", ans.x);
  }
  return 0;
}
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