結果

問題 No.2511 Mountain Sequence
ユーザー Misuki
提出日時 2024-01-17 02:10:02
言語 C++23
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 9 ms / 2,000 ms
コード長 4,965 bytes
コンパイル時間 2,527 ms
コンパイル使用メモリ 196,272 KB
実行使用メモリ 6,944 KB
最終ジャッジ日時 2024-09-28 03:08:18
合計ジャッジ時間 4,233 ms
ジャッジサーバーID
(参考情報)
judge2 / judge1
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 32
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 optimize("O2")
#include <algorithm>
#include <array>
#include <bit>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cfenv>
#include <cfloat>
#include <chrono>
#include <cinttypes>
#include <climits>
#include <cmath>
#include <compare>
#include <complex>
#include <concepts>
#include <cstdarg>
#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <fstream>
#include <functional>
#include <initializer_list>
#include <iomanip>
#include <ios>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <new>
#include <numbers>
#include <numeric>
#include <ostream>
#include <queue>
#include <random>
#include <ranges>
#include <set>
#include <span>
#include <sstream>
#include <stack>
#include <streambuf>
#include <string>
#include <tuple>
#include <type_traits>
#include <variant>
//#define int ll
#define INT128_MAX (__int128)(((unsigned __int128) 1 << ((sizeof(__int128) * __CHAR_BIT__) - 1)) - 1)
#define INT128_MIN (-INT128_MAX - 1)
#ifdef DEBUG
#define dbg(x) cout << (#x) << " = " << x << '\n'
#else
#define dbg(x)
#endif
namespace R = std::ranges;
namespace V = std::views;
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ldb = long double;
//#define double ldb
template<class T, size_t N>
ostream& operator<<(ostream& os, const array<T, N> &arr) {
for(const T &X : arr)
os << X << ' ';
return os;
}
template<class T>
ostream& operator<<(ostream& os, const vector<T> &vec) {
for(const T &X : vec)
os << X << ' ';
return os;
}
template<class T>
ostream& operator<<(ostream& os, const set<T> &s) {
for(const T &x : s)
os << x << ' ';
return os;
}
/**
* template name: MontgomeryModInt
* author: Misuki
* reference: https://github.com/NyaanNyaan/library/blob/master/modint/montgomery-modint.hpp#L10
* last update: 2023/11/30
* note: mod should be a prime less than 2^30.
*/
template<uint32_t mod>
struct MontgomeryModInt {
using mint = MontgomeryModInt;
using i32 = int32_t;
using u32 = uint32_t;
using u64 = uint64_t;
static constexpr u32 get_r() {
u32 res = 1, base = mod;
for(i32 i = 0; i < 31; i++)
res *= base, base *= base;
return -res;
}
static constexpr u32 get_mod() {
return mod;
}
static constexpr u32 n2 = -u64(mod) % mod; //2^64 % mod
static constexpr u32 r = get_r(); //-P^{-1} % 2^32
u32 a;
static u32 reduce(const u64 &b) {
return (b + u64(u32(b) * r) * mod) >> 32;
}
static u32 transform(const u64 &b) {
return reduce(u64(b) * n2);
}
MontgomeryModInt() : a(0) {}
MontgomeryModInt(const int64_t &b)
: a(transform(b % mod + mod)) {}
mint pow(u64 k) const {
mint res(1), base(*this);
while(k) {
if (k & 1)
res *= base;
base *= base, k >>= 1;
}
return res;
}
mint inverse() const { return (*this).pow(mod - 2); }
u32 get() const {
u32 res = reduce(a);
return res >= mod ? res - mod : res;
}
mint& operator+=(const mint &b) {
if (i32(a += b.a - 2 * mod) < 0) a += 2 * mod;
return *this;
}
mint& operator-=(const mint &b) {
if (i32(a -= b.a) < 0) a += 2 * mod;
return *this;
}
mint& operator*=(const mint &b) {
a = reduce(u64(a) * b.a);
return *this;
}
mint& operator/=(const mint &b) {
a = reduce(u64(a) * b.inverse().a);
return *this;
}
mint operator-() { return mint() - mint(*this); }
bool operator==(mint b) const {
return (a >= mod ? a - mod : a) == (b.a >= mod ? b.a - mod : b.a);
}
bool operator!=(mint b) const {
return (a >= mod ? a - mod : a) != (b.a >= mod ? b.a - mod : b.a);
}
friend mint operator+(mint a, mint b) { return a += b; }
friend mint operator-(mint a, mint b) { return a -= b; }
friend mint operator*(mint a, mint b) { return a *= b; }
friend mint operator/(mint a, mint b) { return a /= b; }
friend ostream& operator<<(ostream& os, const mint& b) {
return os << b.get();
}
friend istream& operator>>(istream& is, mint& b) {
int64_t val;
is >> val;
b = mint(val);
return is;
}
};
using mint = MontgomeryModInt<998244353>;
/**
* template name: comb
* author: Misuki
* last update: 2023/01/22
* note: remember to call init() before using it.
*/
const int MAX = 400000;
mint fac[MAX], facInv[MAX];
void init() {
fac[0] = 1;
for(int i = 1; i < MAX; i++)
fac[i] = fac[i - 1] * i;
facInv[MAX - 1] = 1 / fac[MAX - 1];
for(int i = MAX - 2; i >= 0; i--)
facInv[i] = facInv[i + 1] * (i + 1);
}
mint C(int a, int b) {
if (b < 0 or a < b)
return 0;
else
return fac[a] * facInv[b] * facInv[a - b];
}
signed main() {
ios::sync_with_stdio(false), cin.tie(NULL);
init();
int n, m; cin >> n >> m;
mint ans = 0;
for(int j = 0; j < m; j++)
ans += C(2 * j, n - 1);
cout << ans << '\n';
return 0;
}
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