Hash Function for unordered_map

unordered_map.cpp

    struct Slope {
      int n, d;  
      Slope(int nn, int dd) {
          int g = gcd(abs(nn), abs(dd));
          // cout << "gcd of " << nn << ", " << dd << " is: " << g << endl;
          n = (g > 0 ? nn/g : nn);
          d = (g > 0 ? dd/g : dd);
      }
    };
    
    struct Cmp {
      size_t operator()(const Slope& k) const {
        return (k.n<<3)^k.d;
      }
      
      size_t operator()(const Slope& k1, const Slope& k2) const {
        return k1.n == k2.n && k1.d == k2.d;
      }
    };
    
    vector<unordered_map<Slope, vector<int>, Cmp, Cmp>> v;