自己写的一个分数模板,在运算操作时进行了防溢出的优化: ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; } ll lcm(ll a, ll b) { return a / gcd(a,b) * b; } struct divi { ll a = ,b = ; }; divi simdiv(divi a) { ll i; divi divn = a; ll k = gcd(a.a,a.b); divn.a /= k; divn.b /= k; )…