107 lines
4.5 KiB
C++
107 lines
4.5 KiB
C++
#include <iostream>
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#include <algorithm> // std::nth_element
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#include "common.h"
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#include "fileHandler.h"
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#include "Timing.h"
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#include "MedianQuicksort.h"
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#include "MedianOfMedians.h"
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#include "RandomizedSelect.h"
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// TODO:
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// - combine partition function
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// - wirth
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// - fix Median of Medians
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// - fix randomized select
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// - use custom swap for just pointer swapping (check difference)
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// comparator function used by qsort
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int compare(const void* a, const void* b)
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{
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// TODO: check why this does not return the same results???
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//return (*(size_t*)a - *(size_t*)b);
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//return (int)(*(int*)a - *(int*)b);
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//return (int)(*(const int*)a - *(const int*)b);
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size_t arg1 = *static_cast<const size_t*>(a);
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size_t arg2 = *static_cast<const size_t*>(b);
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if (arg1 < arg2) return -1;
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if (arg1 > arg2) return 1;
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return 0;
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}
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int main(int argc, char** argv)
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{
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// read test values from input file
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Timing::getInstance()->startRecord("init");
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std::vector<size_t> numbers = readFromFile("testdata");
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std::cout << "just read " << numbers.size() << " values" << std::endl;
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Timing::getInstance()->stopRecord("init");
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// index of median
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if (numbers.size() % 2 == 0)
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{
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// TODO: just use the next element? calc arithmetic mean?
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std::cout << "TODO: define how to handle even datasets" << std::endl;
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return 1;
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}
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size_t idxMed = (numbers.size() - 1) / 2;
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std::cout << "idx median = " << idxMed << " of " << numbers.size() << std::endl;
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// vollständige Sortierung mit Quicksort und Ausgabe des mittleren Elements
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Timing::getInstance()->startRecord("quicksort");
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std::cout << "quicksort median: " << getQuicksortMedian(numbers, idxMed) << std::endl;
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Timing::getInstance()->stopRecord("quicksort");
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// using std quicksort for array
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// TODO: decide how the fuck to create a dynamic size array from vector...
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//size_t* array = new size_t[numbers.size]; // create and fill new array
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//size_t* array = &numbers[0]; // just a pointer to first element as array
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//size_t* array[numbers.size()]; // invalid c++ -> non-constant expression!
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//std::copy(numbers.begin(), numbers.end(), array);
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//size_t* tmp = numbers.data(); // c++11 returns pointer to first elem
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size_t* array = new size_t[999999]; // create and fill new array
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std::copy(numbers.begin(), numbers.end(), array);
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Timing::getInstance()->startRecord("array quicksort");
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std::qsort(array, numbers.size(), sizeof(size_t), compare);
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std::cout << "array quicksort median: " << array[idxMed] << std::endl;
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Timing::getInstance()->stopRecord("array quicksort");
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// comparison "quick" sort with std::sort (introsort)
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std::copy(numbers.begin(), numbers.end(), array);
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Timing::getInstance()->startRecord("array std sort");
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std::sort(array, array + numbers.size());
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std::cout << "array std sort median: " << array[idxMed] << std::endl;
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Timing::getInstance()->stopRecord("array std sort");
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// vorgestellter Randomzized - Select rekursiv implementiert
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Timing::getInstance()->startRecord("randomized select");
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std::cout << "randomized select: " << randomizedSelect(numbers, 0, numbers.size() - 1, idxMed + 1) << std::endl;
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Timing::getInstance()->stopRecord("randomized select");
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// ein weiterer Median - Algorithmus aus der Literatur - implemented with std::vector
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Timing::getInstance()->startRecord("vector median of medians");
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std::cout << "vector median of medians: " << getMedianOfMedians(numbers, idxMed + 1) << std::endl;
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Timing::getInstance()->stopRecord("vector median of medians");
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// ein weiterer Median - Algorithmus aus der Literatur - realized with array
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std::copy(numbers.begin(), numbers.end(), array);
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Timing::getInstance()->startRecord("array median of medians");
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std::cout << "array median of medians: " << getMedianOfMedians(array, 0, numbers.size() - 1, idxMed + 1) << std::endl;
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Timing::getInstance()->stopRecord("array median of medians");
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// noch ein ein weiterer Median - Algorithmus weil wir so cool sind
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Timing::getInstance()->startRecord("wirth");
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// TODO: implement
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Timing::getInstance()->stopRecord("wirth");
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// Verwendung des C++ STL function templates nth_element
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Timing::getInstance()->startRecord("nth element");
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std::nth_element(numbers.begin(), numbers.begin() + idxMed, numbers.end());
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std::cout << "nth element: " << numbers[idxMed] << std::endl;
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Timing::getInstance()->stopRecord("nth element");
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//Timing::getInstance()->getResults();
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Timing::getInstance()->print();
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return 0;
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} |