結果
問題 | No.1627 三角形の成立 |
ユーザー |
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提出日時 | 2021-07-23 22:45:07 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 58 ms / 1,000 ms |
コード長 | 3,300 bytes |
コンパイル時間 | 753 ms |
コンパイル使用メモリ | 84,528 KB |
最終ジャッジ日時 | 2025-01-23 08:29:10 |
ジャッジサーバーID (参考情報) |
judge3 / judge2 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 2 |
other | AC * 22 |
ソースコード
#include <cassert> #include <cstddef> #include <numeric> #include <utility> #include <vector> namespace n91 { class prime_sieve { public: using size_type = std::size_t; private: std::vector<size_type> prime, factor; public: prime_sieve() {} explicit prime_sieve(const size_type size) : prime(), factor(size) { if (size == 0) { return; } std::iota(factor.begin(), factor.end(), static_cast<size_type>(0)); factor[0] = 1; if (size == 1) { return; } factor[1] = 0; prime.reserve(size); for (size_type i{2}; i != size; ++i) { const size_type fi{factor[i]}; if (fi == i) { prime.push_back(i); } for (const size_type p : prime) { if (p > fi) { break; } const size_type ip{i * p}; if (ip >= size) { break; } factor[ip] = p; } } prime.shrink_to_fit(); } size_type len() const noexcept { return factor.size(); } bool is_prime(const size_type i) const noexcept { assert(i < len()); return factor[i] == i; } std::vector<size_type> factorize(size_type i) const noexcept { assert(i != 0); std::vector<size_type> ret; while (i != 1) { ret.push_back(factor[i]); i /= factor[i]; } return std::move(ret); } template <class C> void divisor_zeta(C &c) const noexcept { const size_type n{c.size()}; assert(n <= len()); for (size_type i{0}; i != prime.size() && prime[i] < n; ++i) { for (size_type j{1}; j * prime[i] < n; ++j) { c[j * prime[i]] += c[j]; } } } template <class C> void divisor_mobius(C &c) const noexcept { const size_type n{c.size()}; assert(n <= len()); for (size_type i{0}; i != prime.size() && prime[i] < n; ++i) { for (size_type j{(n - 1) / prime[i]}; j != 0; --j) { c[j * prime[i]] -= c[j]; } } } template <class C> void multiple_zeta(C &c) const noexcept { const size_type n{c.size()}; assert(n <= len()); for (size_type i{0}; i != prime.size() && prime[i] < n; ++i) { for (size_type j{(n - 1) / prime[i]}; j != 0; --j) { c[j] += c[j * prime[i]]; } } } template <class C> void multiple_mobius(C &c) const noexcept { const size_type n{c.size()}; assert(n <= len()); for (size_type i{0}; i != prime.size() && prime[i] < n; ++i) { for (size_type j{1}; j * prime[i] < n; ++j) { c[j] -= c[j * prime[i]]; } } } }; } // namespace n91 #include <algorithm> #include <iostream> #include <vector> #include <atcoder/modint> int main() { using mint = atcoder::modint1000000007; int n, m; std::cin >> n >> m; int A = std::max(n, m); std::vector<mint> a(A, 0); const mint inv2 = mint(1) / 2; for (int d = 1; d != A; d += 1) { mint h = 0, v = 0; { mint x = (n - 1) / d; h = x * n - d * x * (x + 1) * inv2; } { mint x = (m - 1) / d; v = x * m - d * x * (x + 1) * inv2; } a[d] = 2 * h * v + n * v + m * h; } n91::prime_sieve(A).multiple_mobius(a); mint ans = [&]() { mint x = mint(n) * m; return x * (x - 1) * (x - 2) / 6; }(); for (int d = 1; d != A; d += 1) { ans -= a[d] * (d - 1); } std::cout << ans.val() << "\n"; return 0; }