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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <memory.h>
  4. #include <stdint.h>
  5. #include <float.h>
  6. #include <sys/time.h>
  7.  
  8. #define ELEMS 9000000
  9. #define TOPSS 1000
  10.  
  11. typedef double val_t;
  12.  
  13. inline static double baka_sec_count(void) {
  14.     struct timeval tv;
  15.     gettimeofday(&tv, NULL);
  16. 	return (double)tv.tv_sec + ((double)tv.tv_usec / 1000000.0);
  17.  
  18. }
  19.  
  20. inline static uint64_t rand64(void) {
  21. 	static uint64_t x = 88172645463325252ULL;
  22. 	x = x ^ (x << 13);
  23. 	x = x ^ (x >> 7);
  24. 	return x = x ^ (x << 17);
  25. }
  26.  
  27. inline static val_t* alloc_data(int n_) {
  28. 	val_t* p = (val_t*)malloc(sizeof(val_t) * n_);
  29.  
  30. 	for (int i = 0; i < n_; ++i) {
  31. 		p[i] = rand64();
  32. 	}
  33.  
  34. 	return p;
  35. }
  36.  
  37. inline static void aho_select(val_t* arr_, int n_, val_t* top_, int k_) {
  38.  
  39. 	for (int i = 0; i < k_; ++i) {
  40. 		top_[i] = -DBL_MAX;
  41. 	}
  42.  
  43. 	for (int i = 0; i < n_; ++i) {
  44. 		for (int j = 0; j < k_; ++j) {
  45. 			if (top_[j] < arr_[i]) {
  46. 				for (int l = k_ - 1; l > j; --l) {
  47. 					top_[l] = top_[l - 1];
  48. 				}
  49. 				top_[j] = arr_[i];
  50. 				break;
  51. 			}
  52. 		}
  53. 	}
  54. }
  55.  
  56. inline static void free_data(double* p_) {
  57. 	free(p_);
  58. }
  59.  
  60. int main(int argc, char* argv[]) {
  61. 	val_t  top[1000];
  62. 	val_t* p1 = alloc_data(ELEMS);
  63. 	double s;
  64. 	double e;
  65.  
  66. 	s = baka_sec_count();
  67. 	aho_select(p1, ELEMS, top, sizeof(top) / sizeof(val_t));
  68. 	e = baka_sec_count();
  69. 	fprintf(stderr, "turnaround time ::= %.04lf sec\n", e-s);
  70.  
  71. 	free_data(p1);
  72. 	return 0;
  73. }
  74.  
Success #stdin #stdout #stderr 4.9s 71456KB
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Standard input is empty
stdout
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Standard output is empty
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turnaround time ::= 4.8076 sec
https://ideone.com/GZWy0t
language:
C (gcc 8.3)
created:
5 years ago
visibility:
public

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