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  1. #include <iostream>
  2. #include <random>
  3.  
  4. struct Color {
  5. 	Color(unsigned char r, unsigned char g, unsigned char b) : r(r), g(g), b(b) {}
  6. 	unsigned char r, g, b;
  7. };
  8.  
  9. std::ostream &operator<<(std::ostream &out, const Color &c) {
  10. 	return out << "(" << (int)c.r << ", " << (int)c.g << ", " << (int)c.b << ")";
  11. }
  12.  
  13. Color random_color(int j, std::mt19937 &gen) {
  14. 	std::uniform_int_distribution<int> distrib(1, 0xFFFFFF);
  15. 	int color = distrib(gen);
  16. 	int r = color & 0xFF;
  17. 	int g = (color >> 8) & 0xFF;
  18. 	int b = (color >> 16) & 0xFF;
  19.  
  20. 	double l = sqrt(0.299*r*r + 0.587*g*g + 0.114*b*b);
  21. 	double c = j/l;
  22. 	return Color(c*r, c*g, c*b);
  23. }
  24.  
  25.  
  26. int main() {
  27. 	std::random_device rd;
  28. 	std::mt19937 gen(rd());
  29.  
  30. 	for (int j : { 0, 1, 2, 10, 50, 100, 200, 243, 254, 255 }) {
  31. 		std::cout << "j = " << j << ", color = " << random_color(j, gen) << std::endl; 
  32. 	}
  33. }
Success #stdin #stdout 0s 3416KB
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stdin
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Standard input is empty
stdout
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j = 0, color = (0, 0, 0)
j = 1, color = (0, 1, 1)
j = 2, color = (1, 1, 4)
j = 10, color = (8, 10, 12)
j = 50, color = (54, 25, 104)
j = 100, color = (54, 116, 99)
j = 200, color = (249, 189, 55)
j = 243, color = (165, 26, 190)
j = 254, color = (85, 65, 119)
j = 255, color = (49, 245, 130)
https://ideone.com/c5FuHz
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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