Method Num

code/mathematics/ntt.cpp:8–8

struct Num {
  int x;
  Num(ll _x=0) { x = (_x%mod+mod)%mod; }
  Num operator +(const Num &b) { return x + b.x; }
  Num operator -(const Num &b) const { return x - b.x; }
  Num operator *(const Num &b) const { return (ll)x * b.x; }