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  1. #include <iostream>
  2. #include <list>
  3. #include <algorithm>
  4. using namespace std;
  5.  
  6. template<class T>
  7. struct PredRetainMax;
  8.  
  9. template<class Time, class Val>
  10. struct PredRetainMax<std::pair<Time, Val>>
  11. {
  12. 	PredRetainMax(Time cutoff, Val& m) :_cutoff(cutoff), _max(m) {}
  13. 	bool operator()(const std::pair<Time, Val>& s)
  14. 	{
  15.         //if older than cutoff, remove
  16.         if (s.first < _cutoff) return true;
  17.         //otherwise, keep and update max
  18.         _max = std::max(_max, s.second);
  19.         return false;
  20. 	}
  21. 	Val get() { return _max; }
  22. private:
  23. 	Time _cutoff;
  24. 	Val& _max;
  25. };
  26.  
  27. std::ostream& operator<<(std::ostream& ostr, const std::list<std::pair<unsigned, double>>& list)
  28. {
  29. 	for (auto &i : list) {
  30. 		ostr << "<" << i.first << "," << i.second << "> ";
  31. 	}
  32. 	return ostr;
  33. }
  34.  
  35. int main()
  36. {
  37. 	using sample = std::pair<unsigned, double>;
  38. 	using pred = PredRetainMax<sample>;
  39.  
  40. 	sample a{ 1,12.2 };
  41. 	sample b{ 2,11.778 };
  42. 	sample c{ 3,9.2 };
  43. 	sample d{ 4,-2.6 };
  44. 	sample e{ 5,10.1 };
  45.  
  46. 	std::list<sample> samples{ d,c,b,a };
  47. 	cout << "original list is: " << samples << endl << endl;
  48.  
  49. 	double maxval(-std::numeric_limits<double>::infinity());
  50. 	//eliminate samples older than 2
  51. 	samples.remove_if(pred(2, maxval));
  52. 	cout << "max is: " << maxval << ", list is: " << samples << endl << endl;
  53.  
  54. 	//add new value
  55. 	samples.push_front(e);
  56. 	//reset max
  57. 	maxval = -std::numeric_limits<double>::infinity();
  58. 	//eliminate samples older than 2
  59. 	samples.remove_if(pred(2, maxval));
  60. 	cout << "max is: " << maxval << ", list is: " << samples << endl << endl;
  61.  
  62. 	//reset max
  63. 	maxval = -std::numeric_limits<double>::infinity();
  64. 	//eliminate samples older than 3
  65. 	samples.remove_if(pred(3, maxval));
  66. 	cout << "max is: " << maxval << ", list is: " << samples << endl << endl;
  67.  
  68. 	return 0;
  69. }
Success #stdin #stdout 0s 16064KB
comments (?)
stdin 
Standard input is empty
stdout 
original list is: <4,-2.6> <3,9.2> <2,11.778> <1,12.2> 

max is: 11.778, list is: <4,-2.6> <3,9.2> <2,11.778> 

max is: 11.778, list is: <5,10.1> <4,-2.6> <3,9.2> <2,11.778> 

max is: 10.1, list is: <5,10.1> <4,-2.6> <3,9.2>
https://ideone.com/qs153j
max value of a windowed stream, Pred
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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