結果

問題 No.2351 Butterfly in Summer
ユーザー abc23abc23
提出日時 2023-06-16 21:37:03
言語 C++23
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 68 ms / 2,000 ms
コード長 7,724 bytes
コンパイル時間 6,328 ms
コンパイル使用メモリ 308,196 KB
実行使用メモリ 50,436 KB
最終ジャッジ日時 2023-09-06 18:57:55
合計ジャッジ時間 9,402 ms
ジャッジサーバーID
（参考情報） 		judge14 / judge13
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 63 ms
50,396 KB
testcase_01 AC 62 ms
50,256 KB
testcase_02 AC 64 ms
50,240 KB
testcase_03 AC 64 ms
50,240 KB
testcase_04 AC 64 ms
50,336 KB
testcase_05 AC 63 ms
50,256 KB
testcase_06 AC 64 ms
50,252 KB
testcase_07 AC 63 ms
50,396 KB
testcase_08 AC 63 ms
50,256 KB
testcase_09 AC 62 ms
50,436 KB
testcase_10 AC 64 ms
50,252 KB
testcase_11 AC 63 ms
50,260 KB
testcase_12 AC 64 ms
50,304 KB
testcase_13 AC 63 ms
50,264 KB
testcase_14 AC 63 ms
50,260 KB
testcase_15 AC 64 ms
50,244 KB
testcase_16 AC 62 ms
50,304 KB
testcase_17 AC 63 ms
50,244 KB
testcase_18 AC 68 ms
50,240 KB
testcase_19 AC 63 ms
50,284 KB
testcase_20 AC 63 ms
50,240 KB
testcase_21 AC 62 ms
50,268 KB
testcase_22 AC 62 ms
50,260 KB
testcase_23 AC 64 ms
50,276 KB
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 # 

#if !__INCLUDE_LEVEL__

#include __FILE__
template<int MOD> struct Fp {
	long long val;
	constexpr Fp(long long v = 0) noexcept : val(v % MOD) {
		if (val < 0) val += MOD;
	}
	constexpr int getmod() { return MOD; }
	constexpr Fp operator - () const noexcept {
		return val ? MOD - val : 0;
	}
	constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; }
	constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; }
	constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; }
	constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; }
	constexpr Fp& operator += (const Fp& r) noexcept {
		val += r.val;
		if (val >= MOD) val -= MOD;
		return *this;
	}
	constexpr Fp& operator -= (const Fp& r) noexcept {
		val -= r.val;
		if (val < 0) val += MOD;
		return *this;
	}
	constexpr Fp& operator *= (const Fp& r) noexcept {
		val = val * r.val % MOD;
		return *this;
	}
	constexpr Fp& operator /= (const Fp& r) noexcept {
		long long a = r.val, b = MOD, u = 1, v = 0;
		while (b) {
			long long t = a / b;
			a -= t * b; swap(a, b);
			u -= t * v; swap(u, v);
		}
		val = val * u % MOD;
		if (val < 0) val += MOD;
		return *this;
	}
	constexpr bool operator == (const Fp& r) const noexcept {
		return this->val == r.val;
	}
	constexpr bool operator != (const Fp& r) const noexcept {
		return this->val != r.val;
	}
	friend constexpr ostream& operator << (ostream &os, const Fp<MOD>& x) noexcept {
		return os << x.val;
	}
	static constexpr Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept {
		if (n == 0) return 1;
		auto t = modpow(a, n / 2);
		t = t * t;
		if (n & 1) t = t * a;
		return t;
	}
};
// const int MOD = 1000000007;
const int MOD = 998244353;
using mint = Fp<MOD>;

// https://drken1215.hatenablog.com/entry/2018/06/08/210000
// 前処理 COMinit(): O(n)
// クエリ処理 COM(n, k): O(1)

const int MAXCOM = 2e6+5;
// const int MOD = 1000000007;
long long fac[MAXCOM], finv[MAXCOM], inv[MAXCOM];

// テーブルを作る前処理
void COMinit() {
	fac[0] = fac[1] = 1;
	finv[0] = finv[1] = 1;
	inv[1] = 1;
	for (int i = 2; i < MAXCOM; i++){
		fac[i] = fac[i - 1] * i % MOD;
		inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
		finv[i] = finv[i - 1] * inv[i] % MOD;
	}
}

// 二項係数計算
long long COM(int n, int k){
	if (n < k) return 0;
	if (n < 0 || k < 0) return 0;
	return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}


struct Solver {
void solve() {
	COMinit();
	ll n,k;cin>>n>>k;
	mint ans=COM(k,2);
	ans*=n*2;

	ans/=mint::modpow(k,n);
	cout<<ans<<endl;
}};

signed main() {
	int ts = 1;
	// scanf("%lld",&ts);
	rep(ti,ts) {
		Solver solver;
		solver.solve();
	}
	return 0;
}

#else

#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;

using namespace std;

#define int ll

using ll=long long;
using ld = long double;
using uint = unsigned;
using ull = unsigned long long;
using P=pair<int,int>;
using TP=tuple<int,int,int>;

const int INF = 1001001001;
const long long INFL = 3e18;
const int MAX = 2e6+5;

#define FOR1(a) for (ll _ = 0; _ < ll(a); ++_)
#define FOR2(i, a) for (ll i = 0; i < ll(a); ++i)
#define FOR3(i, a, b) for (ll i = a; i < ll(b); ++i)
#define FOR4(i, a, b, c) for (ll i = a; i < ll(b); i += (c))
#define FOR1_R(a) for (ll i = (a)-1; i >= ll(0); --i)
#define FOR2_R(i, a) for (ll i = (a)-1; i >= ll(0); --i)
#define FOR3_R(i, a, b) for (ll i = (b)-1; i >= ll(a); --i)
#define FOR4_R(i, a, b, c) for (ll i = (b)-1; i >= ll(a); i -= (c))
#define overload4(a, b, c, d, e, ...) e
#define rep(...) overload4(__VA_ARGS__, FOR4, FOR3, FOR2, FOR1)(__VA_ARGS__)
#define rrep(...) overload4(__VA_ARGS__, FOR4_R, FOR3_R, FOR2_R, FOR1_R)(__VA_ARGS__)
#define fore(i,a) for(auto &i:a)

#define all(x) x.begin(),x.end() 
#define allr(x) x.rbegin(),x.rend() 
#define sz(x) ((int)(x).size())
#define bp(x) (__builtin_popcountll((long long)(x)))
#define elif else if
#define mpa make_pair
#define bit(n) (1LL<<(n))
#define LB(c, x) distance((c).begin(), lower_bound(all(c), (x)))
#define UB(c, x) distance((c).begin(), upper_bound(all(c), (x)))

template<typename T> using V = vector<T>;
template<typename T> using max_heap = priority_queue<T>;
template<typename T> using min_heap = priority_queue<T, vector<T>, greater<>>;
template<typename T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<typename T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
template<typename T>string join(const T&v,const string& d=""){stringstream s;rep(i,sz(v))(i?s<<d:s)<<v[i];return s.str();}
template<typename T>ostream& operator<<(ostream&o,const vector<T>&v){if(sz(v))o<<join(v," ");return o;}
template<typename T1,typename T2>ostream& operator<<(ostream&o,const pair<T1,T2>&v){return o<<v.first<<","<<v.second;}
template<typename Tx, typename Ty>Tx dup(Tx x, Ty y){return (x+y-1)/y;}
template<typename T>ll suma(const vector<T>&a){ll res(0);for(auto&&x:a)res+=x;return res;}
template<typename T>ll suma(const V<V<T>>&a){ll res(0);for(auto&&x:a)res+=suma(x);return res;}
template<typename T>void uni(T& a){sort(all(a));a.erase(unique(all(a)),a.end());}
template<typename T>void prepend(vector<T>&a,const T&x){a.insert(a.begin(),x);}
template<typename T>T vgcd(T m, T n) {return std::gcd(m, n);}
template<typename T, typename... Args>T vgcd(T a, Args... args) {return vgcd(a, vgcd(args...));}

void print(){ putchar(' '); }
void print(bool a){ printf("%d", a); }
// void print(int a){ printf("%d", a); }
void print(unsigned a){ printf("%u", a); }
void print(long a){ printf("%ld", a); }
void print(long long a){ printf("%lld", a); }
void print(unsigned long long a){ printf("%llu", a); }
void print(char a){ printf("%c", a); }
void print(char *a){ printf("%s", a); }
void print(const char *a){ printf("%s", a); }
void print(double a){ printf("%.15f", a); }
void print(long double a){ printf("%.15Lf", a); }
void print(const string& a){ for(auto&& i : a) print(i); }
template<typename T> void print(const complex<T>& a){ if(a.real() >= 0) print('+'); print(a.real()); if(a.imag() >= 0) print('+'); print(a.imag()); print('i'); }
template<typename T> void print(const vector<T>&);
template<typename T, size_t size> void print(const array<T, size>&);
template<typename T, typename L> void print(const pair<T, L>& p);
template<typename T, size_t size> void print(const T (&)[size]);
template<typename T> void print(const vector<T>& a){ if(a.empty()) return; print(a[0]); for(auto i = a.begin(); ++i != a.end(); ){ putchar(' '); print(*i); } }
template<typename T> void print(const deque<T>& a){ if(a.empty()) return; print(a[0]); for(auto i = a.begin(); ++i != a.end(); ){ putchar(' '); print(*i); } }
template<typename T, size_t size> void print(const array<T, size>& a){ print(a[0]); for(auto i = a.begin(); ++i != a.end(); ){ putchar(' '); print(*i); } }
template<typename T, typename L> void print(const pair<T, L>& p){ print(p.first); putchar(' '); print(p.second); }
template<typename T, size_t size> void print(const T (&a)[size]){ print(a[0]); for(auto i = a; ++i != end(a); ){ putchar(' '); print(*i); } }
template<typename T> void print(const T& a){ cout << a; }
int out(){ putchar('\n'); return 0; }
template<typename T> int out(const T& t){ print(t); putchar('\n'); return 0; }
template<typename Head, typename... Tail> int out(const Head& head, const Tail&... tail){ print(head); putchar(' '); out(tail...); return 0; }


ll binary_search(function<bool(ll)> check, ll ok, ll ng) {
assert(check(ok));
	while (abs(ok - ng) > 1) {
		auto x = (ng + ok) / 2;
		if (check(x))
			ok = x;
		else
			ng = x;
	}
	return ok;
}

#endif
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