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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 mix1(uint16_t a, uint16_t b) {
  20.     // uint32_t a = a16;
  21.     // uint32_t b = b16;
  22.  
  23.     return
  24.     (a & 0b1) << 0 | (a & 0b10) << 1| (a & 0b100) << 2| (a & 0b1000) << 3| (a & 0b10000) << 4| (a & 0b100000) << 5| (a & 0b1000000) << 6| (a & 0b10000000) << 7| (a & 0b100000000) << 8| (a & 0b1000000000) << 9| (a & 0b10000000000) << 10| (a & 0b100000000000) << 11| (a & 0b1000000000000) << 12| (a & 0b10000000000000) << 13| (a & 0b100000000000000) << 14| (a & 0b1000000000000000) << 15
  25.    |(b & 0b1) << 1 | (b & 0b10) << 2| (b & 0b100) << 3| (b & 0b1000) << 4| (b & 0b10000) << 5| (b & 0b100000) << 6| (b & 0b1000000) << 7| (b & 0b10000000) << 8| (b & 0b100000000) << 9| (b & 0b1000000000) << 10| (b & 0b10000000000) << 11| (b & 0b100000000000) << 12| (b & 0b1000000000000) << 13| (b & 0b10000000000000) << 14| (b & 0b100000000000000) << 15| (b & 0b1000000000000000) << 16;
  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(mix1);
  53.     benchmark(mix1);
  54.     return 0;
  55. }
Success #stdin #stdout 1.7s 5316KB
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Standard input is empty
stdout
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test...passed!
benchmark...end! elapsed:1.68964s 4192649710
https://ideone.com/XtRQc7
language:
C++14 (gcc 8.3)
created:
3 days ago
visibility:
public

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