Submission #1008794

#TimeUsernameProblemLanguageResultExecution timeMemory
1008794nima_aryanSkyscraper (JOI16_skyscraper)C++17
15 / 100
270 ms32920 KiB
/** * author: NimaAryan * created: 2024-06-26 20:39:48 **/ #include <bits/stdc++.h> using namespace std; #ifdef LOCAL #include "algo/debug.h" #endif using i64 = long long; template <typename T> T inverse(T a, T m) { T u = 0, v = 1; while (a != 0) { T t = m / a; m -= t * a; swap(a, m); u -= t * v; swap(u, v); } assert(m == 1); return u; } template <typename T> class Modular { public: using Type = typename decay<decltype(T::value)>::type; constexpr Modular() : value() {} template <typename U> Modular(const U& x) { value = normalize(x); } template <typename U> static Type normalize(const U& x) { Type v; if (-mod() <= x && x < mod()) v = static_cast<Type>(x); else v = static_cast<Type>(x % mod()); if (v < 0) v += mod(); return v; } const Type& operator()() const { return value; } template <typename U> explicit operator U() const { return static_cast<U>(value); } constexpr static Type mod() { return T::value; } Modular& operator+=(const Modular& other) { if ((value += other.value) >= mod()) value -= mod(); return *this; } Modular& operator-=(const Modular& other) { if ((value -= other.value) < 0) value += mod(); return *this; } template <typename U> Modular& operator+=(const U& other) { return *this += Modular(other); } template <typename U> Modular& operator-=(const U& other) { return *this -= Modular(other); } Modular& operator++() { return *this += 1; } Modular& operator--() { return *this -= 1; } Modular operator++(int) { Modular result(*this); *this += 1; return result; } Modular operator--(int) { Modular result(*this); *this -= 1; return result; } Modular operator-() const { return Modular(-value); } template <typename U = T> typename enable_if<is_same<typename Modular<U>::Type, int>::value, Modular>::type & operator*=(const Modular& rhs) { #ifdef _WIN32 uint64_t x = static_cast<int64_t>(value) * static_cast<int64_t>(rhs.value); uint32_t xh = static_cast<uint32_t>(x >> 32), xl = static_cast<uint32_t>(x), d, m; asm( "divl %4; \n\t" : "=a" (d), "=d" (m) : "d" (xh), "a" (xl), "r" (mod()) ); value = m; #else value = normalize(static_cast<int64_t>(value) * static_cast<int64_t>(rhs.value)); #endif return *this; } template <typename U = T> typename enable_if<is_same<typename Modular<U>::Type, long long>::value, Modular>::type & operator*=(const Modular& rhs) { long long q = static_cast<long long>(static_cast<long double>(value) * rhs.value / mod()); value = normalize(value * rhs.value - q * mod()); return *this; } template <typename U = T> typename enable_if < !is_integral<typename Modular<U>::Type>::value, Modular >::type & operator*=(const Modular& rhs) { value = normalize(value * rhs.value); return *this; } Modular& operator/=(const Modular& other) { return *this *= Modular(inverse(other.value, mod())); } friend const Type& abs(const Modular& x) { return x.value; } template <typename U> friend bool operator==(const Modular<U>& lhs, const Modular<U>& rhs); template <typename U> friend bool operator<(const Modular<U>& lhs, const Modular<U>& rhs); template <typename V, typename U> friend V& operator>>(V& stream, Modular<U>& number); private: Type value; }; template <typename T> bool operator==(const Modular<T>& lhs, const Modular<T>& rhs) { return lhs.value == rhs.value; } template <typename T, typename U> bool operator==(const Modular<T>& lhs, U rhs) { return lhs == Modular<T>(rhs); } template <typename T, typename U> bool operator==(U lhs, const Modular<T>& rhs) { return Modular<T>(lhs) == rhs; } template <typename T> bool operator!=(const Modular<T>& lhs, const Modular<T>& rhs) { return !(lhs == rhs); } template <typename T, typename U> bool operator!=(const Modular<T>& lhs, U rhs) { return !(lhs == rhs); } template <typename T, typename U> bool operator!=(U lhs, const Modular<T>& rhs) { return !(lhs == rhs); } template <typename T> bool operator<(const Modular<T>& lhs, const Modular<T>& rhs) { return lhs.value < rhs.value; } template <typename T> Modular<T> operator+(const Modular<T>& lhs, const Modular<T>& rhs) { return Modular<T>(lhs) += rhs; } template <typename T, typename U> Modular<T> operator+(const Modular<T>& lhs, U rhs) { return Modular<T>(lhs) += rhs; } template <typename T, typename U> Modular<T> operator+(U lhs, const Modular<T>& rhs) { return Modular<T>(lhs) += rhs; } template <typename T> Modular<T> operator-(const Modular<T>& lhs, const Modular<T>& rhs) { return Modular<T>(lhs) -= rhs; } template <typename T, typename U> Modular<T> operator-(const Modular<T>& lhs, U rhs) { return Modular<T>(lhs) -= rhs; } template <typename T, typename U> Modular<T> operator-(U lhs, const Modular<T>& rhs) { return Modular<T>(lhs) -= rhs; } template <typename T> Modular<T> operator*(const Modular<T>& lhs, const Modular<T>& rhs) { return Modular<T>(lhs) *= rhs; } template <typename T, typename U> Modular<T> operator*(const Modular<T>& lhs, U rhs) { return Modular<T>(lhs) *= rhs; } template <typename T, typename U> Modular<T> operator*(U lhs, const Modular<T>& rhs) { return Modular<T>(lhs) *= rhs; } template <typename T> Modular<T> operator/(const Modular<T>& lhs, const Modular<T>& rhs) { return Modular<T>(lhs) /= rhs; } template <typename T, typename U> Modular<T> operator/(const Modular<T>& lhs, U rhs) { return Modular<T>(lhs) /= rhs; } template <typename T, typename U> Modular<T> operator/(U lhs, const Modular<T>& rhs) { return Modular<T>(lhs) /= rhs; } template <typename T, typename U> Modular<T> power(const Modular<T>& a, const U& b) { assert(b >= 0); Modular<T> x = a, res = 1; U p = b; while (p > 0) { if (p & 1) res *= x; x *= x; p >>= 1; } return res; } template <typename T, typename U> Modular<T> operator^(const Modular<T>& lhs, U rhs) { return power(lhs, rhs); }; template <typename T> bool IsZero(const Modular<T>& number) { return number() == 0; } template <typename T> string to_string(const Modular<T>& number) { return to_string(number()); } // U == std::ostream? but done this way because of fastoutput template <typename U, typename T> U& operator<<(U& stream, const Modular<T>& number) { return stream << number(); } // U == std::istream? but done this way because of fastinput template <typename U, typename T> U& operator>>(U& stream, Modular<T>& number) { typename common_type<typename Modular<T>::Type, long long>::type x; stream >> x; number.value = Modular<T>::normalize(x); return stream; } /* using ModType = int; struct VarMod { static ModType value; }; ModType VarMod::value; ModType& md = VarMod::value; using Mint = Modular<VarMod>; */ constexpr int md = (int) 1e9 + 7; using Mint = Modular<std::integral_constant<decay<decltype(md)>::type, md>>; int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int N, L; cin >> N >> L; vector<int> A(N); for (int i = 0; i < N; ++i) { cin >> A[i]; } sort(A.begin(), A.end()); int M = (N + 5) * 1000; int T = M + 1 + L; vector f(N + 1, vector(T + 1, vector<Mint>(3))); f[1][0][0] = 1; f[1][-A[0] + M][1] = 2; f[1][2 * -A[0] + M][2] = 1; for (int i = 1; i < N; ++i) { vector g(N + 1, vector(T + 1, vector<Mint>(3))); for (int c = 1; c <= N; ++c) { for (int s = 0; s <= T; ++s) { { if (c + 1 <= N && s - 2 * A[i] >= 0) { g[c + 1][s - 2 * A[i]][0] += f[c][s][0] * max(0, c - 1); } g[c][s][0] += f[c][s][0] * max(0, 2 * c - 2); if (c - 1 >= 0 && s + 2 * A[i] <= T) { g[c - 1][s + 2 * A[i]][0] += f[c][s][0] * max(0, c - 1); } } { if (c + 1 <= N && s - 2 * A[i] >= 0) { g[c + 1][s - 2 * A[i]][1] += f[c][s][1] * c; } if (c + 1 <= N && s - A[i] >= 0) { g[c + 1][s - A[i]][0] += f[c][s][1]; } g[c][s][1] += f[c][s][1] * max(0, 2 * c - 1); if (s + A[i] <= T) { g[c][s + A[i]][0] += f[c][s][1]; } if (c - 1 >= 0 && s + 2 * A[i] <= T) { g[c - 1][s + 2 * A[i]][1] += f[c][s][1] * max(0, c - 1); } } { if (c + 1 <= N && s - 2 * A[i] >= 0) { g[c + 1][s - 2 * A[i]][2] += f[c][s][2] * (c + 1); } if (c + 1 <= N && s - A[i] >= 0) { g[c + 1][s - A[i]][1] += f[c][s][2] * 2; } g[c][s][2] += f[c][s][2] * 2 * c; if (s + A[i] <= T) { g[c][s + A[i]][1] += f[c][s][2] * 2; } if (c - 1 >= 0 && s + 2 * A[i] <= T) { g[c - 1][s + 2 * A[i]][2] += f[c][s][2] * max(0, c - 1); } } } } f.swap(g); } Mint ans = 0; for (int l = 0; l <= L; ++l) { ans += f[1][l + M][0]; } cout << ans << "\n"; return 0; }
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