結果

問題 No.2794 I Love EDPC-T
ユーザー fuppy_kyopro
提出日時 2024-06-22 00:09:06
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 96 ms / 3,000 ms
コード長 6,728 bytes
コンパイル時間 5,027 ms
コンパイル使用メモリ 269,880 KB
最終ジャッジ日時 2025-02-22 00:04:57
ジャッジサーバーID
（参考情報） 		judge3 / judge1
このコードへのチャレンジ
（要ログイン）
ファイルパターン 結果
sample AC * 3
other AC * 31
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 #
プレゼンテーションモードにする

/*
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
//*/
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
// #define _GLIBCXX_DEBUG
#define DEBUG(x) cerr << #x << ": " << x << endl;
#define DEBUG_VEC(v)                                        \
    cerr << #v << ":";                                      \
    for (int iiiiiiii = 0; iiiiiiii < v.size(); iiiiiiii++) \
        cerr << " " << v[iiiiiiii];                         \
    cerr << endl;
#define DEBUG_MAT(v)                                \
    cerr << #v << endl;                             \
    for (int iv = 0; iv < v.size(); iv++) {         \
        for (int jv = 0; jv < v[iv].size(); jv++) { \
            cerr << v[iv][jv] << " ";               \
        }                                           \
        cerr << endl;                               \
    }
typedef long long ll;
// #define int ll
#define vi vector<int>
#define vl vector<ll>
#define vii vector<vector<int>>
#define vll vector<vector<ll>>
#define pii pair<int, int>
#define pis pair<int, string>
#define psi pair<string, int>
#define pll pair<ll, ll>
template <class S, class T>
pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) {
    return pair<S, T>(s.first + t.first, s.second + t.second);
}
template <class S, class T>
pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template <class S, class T>
ostream &operator<<(ostream &os, pair<S, T> p) {
    os << "(" << p.first << ", " << p.second << ")";
    return os;
}
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i <= (int)(n); i++)
#define rrep(i, n) for (int i = (int)(n) - 1; i >= 0; i--)
#define rrep1(i, n) for (int i = (int)(n); i > 0; i--)
#define REP(i, a, b) for (int i = a; i < b; i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(), c.end()
void YES(bool t = true) {
    cout << (t ? "YES" : "NO") << endl;
}
void Yes(bool t = true) { cout << (t ? "Yes" : "No") << endl; }
void yes(bool t = true) { cout << (t ? "yes" : "no") << endl; }
void NO(bool t = true) { cout << (t ? "NO" : "YES") << endl; }
void No(bool t = true) { cout << (t ? "No" : "Yes") << endl; }
void no(bool t = true) { cout << (t ? "no" : "yes") << endl; }
template <class T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
bool chmin(T &a, const T &b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
T ceil_div(T a, T b) {
    return (a + b - 1) / b;
}
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const long double pi = 3.1415926535897932384626433832795028841971L;
int popcount(ll t) { return __builtin_popcountll(t); }
vector<int> gen_perm(int n) {
    vector<int> ret(n);
    iota(all(ret), 0);
    return ret;
}
// int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
// int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
vi dx = {0, 0, -1, 1}, dy = {-1, 1, 0, 0};
vi dx2 = {1, 1, 0, -1, -1, -1, 0, 1}, dy2 = {0, 1, 1, 1, 0, -1, -1, -1};
struct Setup_io {
    Setup_io() {
        ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
        cout << fixed << setprecision(25);
        cerr << fixed << setprecision(25);
    }
} setup_io;
// constexpr ll MOD = 1000000007;
constexpr ll MOD = 998244353;
// #define mp make_pair
using mint = modint998244353;
const int MAXN = 555555;
vl fact(MAXN);
vl rfact(MAXN);
ll mod_pow(ll x, ll p, ll M = MOD) {
    if (p < 0) {
        x = mod_pow(x, M - 2, M);
        p = -p;
    }
    x %= M;
    ll a = 1;
    while (p) {
        if (p % 2)
            a = a * x % M;
        x = x * x % M;
        p /= 2;
    }
    return a;
}
ll mod_inverse(ll a, ll M = MOD) {
    return mod_pow(a, M - 2, M);
}
void set_fact(ll n, ll M = MOD) {
    fact[0] = 1;
    for (ll i = 1; i <= n; i++) {
        fact[i] = i * fact[i - 1] % M;
    }
    rfact[n] = mod_inverse(fact[n], M);
    for (ll i = n - 1; i >= 0; i--) {
        rfact[i] = (i + 1) * rfact[i + 1] % M;
    }
}
// http://drken1215.hatenablog.com/entry/2018/06/08/210000
ll nCr(ll n, ll r, ll M = MOD) {
    if (r > n) return 0;
    assert(fact[2] == 2);
    ll ret = fact[n];
    if (rfact[r] == 0) {
        rfact[r] = mod_inverse(fact[r], M);
    }
    ret = (ret * rfact[r]) % M;
    if (rfact[n - r] == 0) {
        rfact[n - r] = mod_inverse(fact[n - r], M);
    }
    ret = (ret * rfact[n - r]) % M;
    return ret;
}
ll nHr(ll n, ll r) {
    return nCr(n + r - 1, r);
}
// noimi のライブラリ拝借した
// https://codeforces.com/contest/1942/submission/254160773
// +1 n 個 -1 m 個で累積和 >= 0
mint Catalan(int n, int m) { return nCr(n + m, m) - nCr(n + m, m - 1); }
signed main() {
    int n;
    cin >> n;
    string s;
    cin >> s;
    set_fact(444444);
    rep(i, (int)s.size() - 1) {
        if (s[i] == '<' && s[i + 1] == '<') {
            cout << 0 << endl;
            return 0;
        }
    }
    bool all_low = true;
    rep(i, s.size()) {
        if (s[i] == '<') {
            all_low = false;
            break;
        }
    }
    if (all_low) {
        cout << 0 << endl;
        return 0;
    }
    vi p;
    rep(i, n - 1) {
        if (s[i] == '<') {
            p.push_back(i);
        }
    }
    vi sukima;
    if (p[0] >= 2) {
        sukima.push_back(p[0] - 1);
    }
    for (int i = 0; i < (int)p.size() - 1; i++) {
        int d = p[i + 1] - p[i];
        if (d >= 4) {
            sukima.push_back(d - 3);
        }
    }
    if (p.back() < n - 3) {
        sukima.push_back(n - 2 - p.back() - 1);
    }
    vector<vector<mint>> cs(sukima.size());
    rep(i, sukima.size()) {
        for (int j = 0; sukima[i] + 1 - j >= j; j++) {
            cs[i].push_back(nCr(sukima[i] + 1 - j, j));
        }
    }
    while (cs.size() > 1) {
        vector<vector<mint>> next_cs;
        for (int i = 0; i < cs.size(); i += 2) {
            if (i + 1 < cs.size()) {
                next_cs.push_back(convolution(cs[i], cs[i + 1]));
            } else {
                next_cs.push_back(cs[i]);
            }
        }
        cs = next_cs;
    }
    if (cs.size() == 0) {
        cs.push_back({1});
    }
    mint ans = 0;
    for (int ihan = 0; ihan < cs[0].size(); ihan++) {
        mint x = cs[0][ihan];
        int fu = 1;
        if (ihan % 2 == 1) {
            fu = -1;
        }
        int k = n - (int)p.size() - ihan;
        if (k >= 0) {
            ans += fu * x * Catalan(k, k);
        }
    }
    cout << ans.val() << endl;
}
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
0