RT，这是原先的光速乘：

using ll = long long;
using ull = unsigned ll;
using ld = long double;
ll qmul(ll a, ll b, ll c){
	a%=c, b%=c;
	ll w = (ld)a/c*b;
	ll r = (ull)a*b-(ull)w*c;
	return r<0?r+c:r;
}

那么换成

using ll = __int128;
using ull = unsigned ll;
using ld = __float128;

是否仍能使用