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  1. #include <stdio.h>
  2.  
  3. #define SIZE 250000
  4.  
  5. int a[SIZE], n;
  6.  
  7. long search_statistics(int l, int r, int k)
  8. {
  9. 	while (l < r)
  10. 	{
  11. 		int i = l, j = r;
  12. 		int x = a[(r - l) / 2 + l];
  13.  
  14. 		while (i <= j)
  15. 		{
  16. 			while (a[i] < x) i++;
  17.  
  18. 			while (a[j] > x) j--;
  19.  
  20. 			if (i <= j)
  21. 			{
  22. 				int t = a[i];
  23. 				a[i++] = a[j];
  24. 				a[j--] = t;
  25. 			}
  26. 		}
  27.  
  28. 		if (k <= j)
  29. 			r = j;
  30. 		else if (k >= i)
  31. 			l = i;
  32. 		else
  33. 			break;
  34. 	}
  35.  
  36. 	return a[k];
  37. }
  38.  
  39. int main()
  40. {
  41. 	int i;
  42. 	long double res;
  43.  
  44. 	scanf("%d", &n);
  45.  
  46. 	for (i = 0; i < n; i++)
  47. 		scanf("%d", &a[i]);
  48.  
  49. 	if (n % 2)
  50. 		res = search_statistics(0, n - 1, n / 2);
  51. 	else
  52. 		res = ((long double) search_statistics(0, n - 1, n / 2) / 2) + ((long double) search_statistics(0, n - 1, n / 2 - 1) / 2);
  53.  
  54. 	printf("%.1Lf", res);
  55.  
  56. 	return 0;
  57. }
Success #stdin #stdout 0s 3228KB
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https://ideone.com/3WJtgy
language:
C (gcc 8.3)
created:
11 years ago
visibility:
secret

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