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  1. #include <iostream>
  2. #include <cmath>
  3. #include <iomanip>
  4.  
  5. using namespace std;
  6.  
  7. double F(double, double, double, double);
  8. double f(double, double, double, double);
  9. double sum(double, double, double, int, double, double);
  10.  
  11.  
  12. const double EPS = 10e-7; //dopuszczalny margines bledu
  13.  
  14. int main()
  15. {
  16.     double A, B, C;
  17.     cin >> A >> B >> C;
  18.     if (A < 0) //upewnienie sie, ze wspolczynnik A jest dodatni
  19.     {
  20.         A *= -1;
  21.         B *= -1;
  22.         C *= -1;
  23.     }
  24.  
  25.     int t = 0;
  26.     cin >> t;
  27.     while (t--)
  28.     {
  29.  
  30.         double x1, x2;
  31.         double P; //przyblizenie z zadania
  32.         cin>> x1 >> x2 >> P;
  33.         double S = F(A, B, C, x2) - F(A, B, C, x1); //faktyczne pole
  34.         double E = P - S; //blad (zawsze P >= S)
  35.         E-=EPS;
  36.  
  37.         //cout <<setprecision(7) << fixed << S <<' ';
  38.  
  39.  
  40.         int K = (x2 - x1) * (x2 - x1) * (x2 - x1) * A / 6.0 / E;
  41.  
  42.         K = sqrt(K);
  43.  
  44.  
  45.         K++;
  46.         int k = K;
  47.         while (k > 0)
  48.         {
  49.             if (sum(A, B, C, k, x1, x2) - P < EPS && -1*EPS < sum(A, B, C, k, x1, x2) - P)
  50.             {
  51.                 cout<< k <<endl;
  52.                 break;
  53.  
  54.             }
  55.             k--;
  56.         }
  57.  
  58.         //cout<< k <<endl;
  59.  
  60.  
  61.  
  62.  
  63.  
  64.     }
  65.     return 0;
  66. }
  67.  
  68.  
  69. double f(double A, double B, double C, double x) //funkcja f(x)
  70. {
  71.     return A * x * x + B * x + C;
  72.  
  73. }
  74.  
  75. double sum(double A, double B, double C, int k, double x1, double x2) //zwraca przyblizenie z uzyciem k trapezow
  76. {
  77.     double Dx = x2 - x1;
  78.     double suma = 0;
  79.     suma += f(A, B, C, x1) + f(A, B, C, x2);
  80.     suma /= 2.0;
  81.     for (int i = 1; i <= k -1; i++)
  82.     {
  83.         double temp = x1 + Dx * (1.0 * i) / (1.0 * k);
  84.         suma += f(A, B, C, temp);
  85.     }
  86.     suma  *= Dx / (1.0 *k );
  87.     return abs(suma);
  88. }
  89.  
  90.  
  91.  
  92.  
  93. double F(double A, double B, double C, double x) // funkcja pierwotna od f
  94. {
  95.     return A * x * x * x / 3.0 + B * x * x / 2.0 + C * x * 1.0;
  96.  
  97. }
  98.  
Success #stdin #stdout 0s 4552KB
comments (?)
stdin
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1 1 2
5
0 5 85.000000
0 5 69.375000
0 5 66.481481
0 5 64.168750
0 5 64.168709
stdout
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1
2
3
100
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https://ideone.com/yazEtr
language:
C++14 (gcc 8.3)
created:
3 years ago
visibility:
secret

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