mgs/median-comparison
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moved comparator before main in function; adding std::sort (introsort)

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incredibleLeitman 2020-10-06 18:11:19 +02:00
parent 68ce4f7887
commit 9ea381fdba
1 changed files with 22 additions and 8 deletions
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30
main.cpp
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@ -7,6 +7,20 @@
#include "MedianOfMedians.h" #include "MedianOfMedians.h"
#include "RandomizedSelect.h" #include "RandomizedSelect.h"
// comparator function used by qsort
int compare(const void* a, const void* b)
{
// TODO: check why this does not return the same results???
//return (*(size_t*)a - *(size_t*)b);
//return (int)(*(int*)a - *(int*)b);
//return (int)(*(const int*)a - *(const int*)b);
size_t arg1 = *static_cast<const size_t*>(a);
size_t arg2 = *static_cast<const size_t*>(b);
if (arg1 < arg2) return -1;
if (arg1 > arg2) return 1;
return 0;
}
int main(int argc, char** argv) { int main(int argc, char** argv) {
// read test values from input file // read test values from input file
Timing::getInstance()->startRecord("init"); Timing::getInstance()->startRecord("init");
@ -39,17 +53,17 @@ int main(int argc, char** argv) {
size_t* array = new size_t[999999]; // create and fill new array size_t* array = new size_t[999999]; // create and fill new array
std::copy(numbers.begin(), numbers.end(), array); std::copy(numbers.begin(), numbers.end(), array);
Timing::getInstance()->startRecord("array quicksort"); Timing::getInstance()->startRecord("array quicksort");
std::qsort(array, numbers.size(), sizeof(size_t), [](const void* a, const void* b) std::qsort(array, numbers.size(), sizeof(size_t), compare);
{
size_t arg1 = *static_cast<const size_t*>(a);
size_t arg2 = *static_cast<const size_t*>(b);
if (arg1 < arg2) return -1;
if (arg1 > arg2) return 1;
return 0;
});
std::cout << "array quicksort median: " << array[idxMed] << std::endl; std::cout << "array quicksort median: " << array[idxMed] << std::endl;
Timing::getInstance()->stopRecord("array quicksort"); Timing::getInstance()->stopRecord("array quicksort");
// comparison "quick" sort with std::sort (introsort)
std::copy(numbers.begin(), numbers.end(), array);
Timing::getInstance()->startRecord("array std sort");
std::sort(array, array + numbers.size());
std::cout << "array std sort median: " << array[idxMed] << std::endl;
Timing::getInstance()->stopRecord("array std sort");
// vorgestellter Randomzized - Select rekursiv implementiert // vorgestellter Randomzized - Select rekursiv implementiert
Timing::getInstance()->startRecord("randomized select"); Timing::getInstance()->startRecord("randomized select");
std::cout << "randomized select: " << randomizedSelect(numbers, 0, numbers.size() - 1, idxMed) << std::endl; std::cout << "randomized select: " << randomizedSelect(numbers, 0, numbers.size() - 1, idxMed) << std::endl;