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  1. #include <cmath>
  2. #include <algorithm>
  3. #include <numeric>
  4. #include <vector>
  5. #include <iostream>
  6. #include <set>
  7. #include <string>
  8. #include <map>
  9. #include <unordered_map>
  10. #include <unordered_set>
  11. #include <limits>
  12. #include <functional>
  13. #include <stack>
  14. #include <queue>
  15. #include <random>
  16. using namespace std;
  17.  
  18.  
  19. struct Point2D
  20. {
  21.     int x;
  22.     int y;
  23.  
  24.     bool operator==(const Point2D& other) const
  25.     {
  26.         return x * other.y == y * other.x;
  27.     }
  28. };
  29.  
  30. static int gcd (int a, int b){
  31.     a = abs(a); b = abs(b);
  32.     return (b==0) ? a : gcd(b, a%b);
  33. }
  34.  
  35. namespace std
  36. {
  37.     template <>
  38.     struct hash<Point2D>
  39.     {
  40.         std::size_t operator()(const Point2D& k) const
  41.         {
  42.             // Compute individual hash values for first,
  43.             // second and combine them using XOR
  44.             // and bit shifting:
  45.             int g = gcd(k.x, k.y);
  46.             int a = k.x/g, b = k.y/g;
  47.             return a ^ b;
  48.  
  49.             /*
  50.             int i1 = k.x;
  51.             int i2 = k.y;
  52.             size_t ret = i1;
  53.             ret *= 2654435761U;
  54.             return ret ^ i2;
  55.             */
  56.  
  57.             /*
  58.             return 111;
  59.             */
  60.         }
  61.     };
  62.  
  63. }
  64.  
  65. int solution(vector<Point2D> &A)
  66. {
  67.     unordered_set<Point2D> pointsOnTheSameLine;
  68.  
  69.     for (auto& point : A)
  70.     {
  71.         pointsOnTheSameLine.insert(point);
  72.     }
  73.  
  74.     return static_cast<int>(pointsOnTheSameLine.size());
  75. }
  76.  
  77. int main()
  78. {
  79.     std::random_device rd;     // only used once to initialise (seed) engine
  80.     std::mt19937 rng(rd());    // random-number engine used (Mersenne-Twister in this case)
  81.     std::uniform_int_distribution<int> uni(-10000, 10000); // guaranteed unbiased
  82.  
  83.     int x = 13;
  84.     int y = 7;
  85.     vector<Point2D> v; // { {0, 1}, {0, 2}, {1, 1}, {-1, -1} };
  86.     for (int i = 0; i < 1000; ++i)
  87.     {
  88.         auto random_integer = uni(rng);
  89.         const Point2D curr{x * random_integer, y * random_integer};
  90.         v.push_back(curr);
  91.  
  92.         //cout << "is equal: " << (Point2D{x, y} == curr) << endl;
  93.     }
  94.  
  95.  
  96.  
  97.     cout << solution(v) << endl;
  98.  
  99.     return 0;
  100. }
  101.  
Success #stdin #stdout 0s 4508KB
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https://ideone.com/iS9Qwv
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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