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  1. #include <ctime>
  2. #include <iostream>
  3.  
  4. // テスト用のmix（この関数は遅いよ！これより早いの作ってね！）
  5. uint32_t mix_test(uint16_t a, uint16_t b) {
  6.     uint32_t o = 0;
  7.     for (int i = 0; i < 16; i++) {
  8.         if (a & (1 << i)) o |= 1 << (i * 2 + 0);
  9.         if (b & (1 << i)) o |= 1 << (i * 2 + 1);
  10.     }
  11.     return o;
  12. }
  13.  
  14. // mixはaとbのbitを交互に詰めて返す。aが下位に来る。
  15. // (例)
  16. // a : 1111111111111111
  17. // b : 0000000000000000
  18. // o : 01010101010101010101010101010101
  19. uint32_t mix(uint16_t a, uint16_t b) {
  20. 	uint64_t c = ((uint64_t)b << 32) | a;
  21. 	c = (c | (c << 8)) & 0x00ff00ff00ff00ffULL;
  22. 	c = (c | (c << 4)) & 0x0f0f0f0f0f0f0f0fULL;
  23. 	c = (c | (c << 2)) & 0x3333333333333333ULL;
  24. 	c = (c | (c << 1)) & 0x5555555555555555ULL;
  25.     return uint32_t(c >> 31) | uint32_t(c & 0xffffffff);
  26. }
  27.  
  28. // テスト
  29. void test(uint32_t(*func)(uint16_t, uint16_t)) {
  30.     std::cout << "test...";
  31.     for (int i = 0; i < 100; i++) {
  32.         uint16_t a = rand(), b = rand();
  33.         if (func(a, b) != mix_test(a, b)) {
  34.             std::cout << "failed" << std::endl;
  35.             exit(EXIT_FAILURE);
  36.         }
  37.     }
  38.     std::cout << "passed!" << std::endl;
  39. }
  40.  
  41. // ベンチマーク
  42. void benchmark(uint32_t (*func)(uint16_t, uint16_t)) {
  43.     std::cout << "benchmark...";
  44.     uint32_t dammy = 0;
  45.     double start = clock();
  46.     for (int i = 0; i < 50000000; i++) dammy ^= func(rand(), rand());
  47.     double end = clock();
  48.     std::cout << "end! elapsed:" << (end - start) / CLOCKS_PER_SEC << "s " << dammy << std::endl;
  49. }
  50.  
  51. int main() {
  52.     test(mix);
  53.     benchmark(mix);
  54.     return 0;
  55. }
Success #stdin #stdout 1.86s 5292KB
comments (?)
stdin 
Standard input is empty
stdout 
test...passed!
benchmark...end! elapsed:1.84942s 4192649710
https://ideone.com/97o0Ur
language:
C++14 (gcc 8.3)
created:
2 days ago
visibility:
public

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