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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4.  
  5. #define forn(i, n) for (int i = 0; i < int(n); i++)
  6.  
  7.  
  8. long double getWinProbability(long double ra, long double rb) {
  9.     return 1.0 / (1.0 + pow((long double) 10.0, (rb - ra) / 400.0));
  10. }
  11. long double aggregateRatings(vector<long double> teamRatings)
  12. {
  13.     long double left = 1;
  14.     long double right = 1E4;
  15.  
  16.     for (int tt = 0; tt < 100; tt++) {
  17.         long double r = (left + right) / 2.0;
  18.  
  19.         long double rWinsProbability = 1.0;
  20.         forn(i, teamRatings.size())
  21.             rWinsProbability *= getWinProbability(r, teamRatings[i]);
  22.  
  23.         long double rating = log10(1 / (rWinsProbability) - 1) * 400 + r;
  24.  
  25.         if (rating > r)
  26.             left = r;
  27.         else
  28.             right = r;
  29.     }
  30.  
  31.     return (left + right) / 2.0;
  32. }
  33.  
  34. int main() {
  35. 	vector<long double> teamRating = {2589, 2115, 2411, 2336, 2142, 1939, 2691,
  36. 	2411, 1794, 2123, 2226, 2185, 2106, 2297, 1862, 2164, 2190, 1961, 
  37. 	2753, 2730, 2599, 2516, 3129};
  38. 	cout << aggregateRatings(teamRating);
  39. }
Success #stdin #stdout 0s 4520KB
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https://ideone.com/SGTALm
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
secret

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