Function direction

SheepCup/Round1/f.cpp:21–21

auto rngl = mt19937_64(random_device()());

array<int, 2> direction(array<int, 2> x1, array<int, 2> x2) {return {x2[0] - x1[0], x2[1] - x1[1]};}
bool sgn(array<int, 2> x) {return x[0] > 0 || (x[0] == 0 && x[1] > 0);}
__int128_t cross(array<int, 2> x1, array<int, 2> x2) {return 1ll * x1[0] * x2[1] - 1ll * x1[1] * x2[0];}
__int128_t dot(array<int, 2> x1, array<int, 2> x2) {return 1ll * x1[0] * x2[0] + 1ll * x1[1] * x2[1];}