Fraction 分数类 默认假分数,可自行修改 由于concept的原因 template <typename T> concept is_float_v = std::is_floating_point<T>::value; template <typename T> concept arithmetic =...
#include <bits/stdc++.h> using namespace std; using ll = long long; const int N = 2e6 + 5; bool isnp[N]; int pfactor[N]; vector<int> primes; void init() { i...