結果
問題 | No.1035 Color Box |
ユーザー |
![]() |
提出日時 | 2021-08-10 22:26:04 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 29 ms / 2,000 ms |
コード長 | 4,517 bytes |
コンパイル時間 | 1,185 ms |
コンパイル使用メモリ | 107,252 KB |
最終ジャッジ日時 | 2025-01-23 17:26:02 |
ジャッジサーバーID (参考情報) |
judge2 / judge4 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 2 |
other | AC * 36 |
ソースコード
#include <algorithm>#include <cmath>#include <iomanip>#include <iostream>#include <map>#include <queue>#include <set>#include <string>#include <tuple>#include <vector>#define mkp make_pair#define mkt make_tuple#define rep(i, n) for (int i = 0; i < (n); ++i)#define all(v) v.begin(), v.end()using namespace std;typedef long long ll;const ll MOD = 1e9 + 7;// const ll MOD = 998244353;template <class T>void chmin(T& a, const T& b) {if (a > b) a = b;}template <class T>void chmax(T& a, const T& b) {if (a < b) a = b;}template <long long mod>class modint {private:using T = long long;T a;public:constexpr modint(const long long x = 0) noexcept : a((x % mod + mod) % mod) {}constexpr T& value() noexcept {return a;}constexpr const T& value() const noexcept {return a;}constexpr modint operator-() const noexcept {return modint(0) -= *this;}constexpr modint operator+(const modint& rhs) const noexcept {return modint(*this) += rhs;}constexpr modint operator-(const modint& rhs) const noexcept {return modint(*this) -= rhs;}constexpr modint operator*(const modint& rhs) const noexcept {return modint(*this) *= rhs;}constexpr modint operator/(const modint& rhs) const noexcept {return modint(*this) /= rhs;}constexpr modint& operator+=(const modint& rhs) noexcept {a += rhs.a;if (a >= mod) a -= mod;return *this;}constexpr modint& operator-=(const modint& rhs) noexcept {if (a < rhs.a) a += mod;a -= rhs.a;return *this;}constexpr modint& operator*=(const modint& rhs) noexcept {a = a * rhs.a % mod;return *this;}constexpr modint& operator/=(const modint& rhs) noexcept {return *this *= rhs.inv();}constexpr bool operator==(const modint& rhs) const noexcept {return a == rhs.a;}constexpr bool operator!=(const modint& rhs) const noexcept {return not(*this == rhs);}constexpr modint pow(long long k) const noexcept {modint ret(1);modint x = k > 0 ? *this : this->inv();k = abs(k);while (k > 0) {if (k & 1) ret *= x;x *= x;k >>= 1;}return ret;}constexpr modint inv() const noexcept {return pow(mod - 2);}friend std::ostream& operator<<(std::ostream& os, const modint& X) noexcept {return os << X.a;}friend std::istream& operator>>(std::istream& is, modint& X) noexcept {is >> X.a;X.a %= mod;if (X.a < 0) X.a += mod;return is;}};template <typename T>struct Combination {int MAX_N = 1'000'010;vector<T> fac, ifac, inv;Combination(int MAX_N = 1'000'010) : MAX_N(MAX_N), fac(MAX_N), ifac(MAX_N), inv(MAX_N) {fac[0] = 1, ifac[0] = 1, inv[0] = 1;for (int i = 1; i < MAX_N; ++i) {fac[i] = fac[i - 1] * i;}ifac[MAX_N - 1] = T(1) / fac[MAX_N - 1];for (int i = MAX_N - 1; i > 0; --i) {ifac[i - 1] = ifac[i] * i;}for (int i = MAX_N - 1; i > 0; --i) {inv[i] = ifac[i] * fac[i - 1];}}T perm(int n, int k) {if (n < k || n < 0 || k < 0)return 0;elsereturn fac[n] * ifac[n - k];}T comb(int n, int k) {if (n < k || n < 0 || k < 0)return 0;elsereturn fac[n] * ifac[k] * ifac[n - k];}T hcomb(int n, int r) { // this size is really ok??if (n == 0 && r == 0)return 1;else if (n < 0 || r < 0)return 0;elsereturn comb(n + r - 1, r);}T binom(ll _n, int k) {if (_n < k || _n < 0 || k < 0) return 0;T n = _n;T res = 1;for (int i = 0; i < k; i++) res = res * (n - i);res *= ifac[k];return res;}};using mint = modint<1000000007>;void solve() {Combination<mint> math;int N, M;cin >> N >> M;vector<mint> dp(M + 1, 0);for (int i = 1; i <= M; i++) {mint res = math.comb(M, i) * mint(i).pow(N);res -= dp[i - 1];dp[i] = res;}mint ans = dp[M];cout << ans << endl;}int main() {cin.tie(nullptr);ios::sync_with_stdio(false);solve();return 0;}