对顺序搜索算法的测试

先利用之前一篇：《对产生不重复随机数组的算法测试》中的算法产生不重复随机数组，个数为1亿个元素

#include <algorithm>#include <time.h>#include <Windows.h>#include <iostream>using namespace std;typedef long long int _INT64;const unsigned len = 100000000;_INT64 arr[len] = {0};void getRandArrayNoRepeat(){for (unsigned i=0; i<len; ++i)arr[i] = i;random_shuffle(arr, arr+len);}_INT64 ssearch1(_INT64 t){ for (unsigned i=0; i<len; ++i) { if (arr[i] == t)return i; } return -1;}_INT64 ssearch3(_INT64 t){arr[len-1] = t;unsigned i;for (i=0; ; i+=8){if (arr[i ] == t) { break; }if (arr[i+1] == t) { i+=1; break; }if (arr[i+2] == t) { i+=2; break; }if (arr[i+3] == t) { i+=3; break; }if (arr[i+4] == t) { i+=4; break; }if (arr[i+5] == t) { i+=5; break; }if (arr[i+6] == t) { i+=6; break; }if (arr[i+7] == t) { i+=7; break; }}if (i == len-1)return -1;elsereturn i;}_INT64 ssearch2(_INT64 t){_INT64 hold = arr[len-1];arr[len-1] = t;unsigned i;for (i=0; ; ++i){if (arr[i] == t)break;}arr[len-1] = hold;if (i == len-1)return -1;elsereturn i;}int main(){getRandArrayNoRepeat();//test1DWORD stime = GetTickCount();cout << "68204826 is in " << ssearch1(68204826) <<'/n';;DWORD test1 = GetTickCount();cout << "ssearch1's running time = " << test1 - stime << " ms." <<'/n';//test2stime = GetTickCount();cout << "68204826 is in " << ssearch2(68204826) <<'/n';;DWORD test2 = GetTickCount();cout << "ssearch2's running time = " << test2 - stime << " ms." <<'/n';//test3stime = GetTickCount();cout << "68204826 is in " << ssearch3(68204826) <<'/n';;DWORD test3 = GetTickCount();cout << "ssearch3's running time = " << test3 - stime << " ms." <<'/n';return 0;} 

 

测试运行结果：

68204826 is in 94856064

ssearch1's running time = 313 ms.

68204826 is in 94856064

ssearch2's running time = 328 ms.

加速5%

68204826 is in 94856064

ssearch3's running time = 234 ms.

加速10-20%