int main() {
std::srand(static_cast<unsigned int>(time(nullptr)));
//checkNthElementAlgo();
const char* inputFilePath = { "Resources/numbers.txt" };
PerformanceMonitor monitor;
std::vector<int> originalNumbers;
if (readNumbersFromFile) {
originalNumbers.reserve(2000000);
std::cout << "Reading file..." << std::endl;
if (utils::readFile(inputFilePath, originalNumbers) != utils::STATUS_SUCCESS) {
utils::exitWithError();
}
std::cout << "Processing " << originalNumbers.size() << " integers" << std::endl;
// Preprocessing for testing purposes:
std::cout << "Shuffeling values..." << std::endl;
std::random_shuffle(originalNumbers.begin(), originalNumbers.end());
}
else {
originalNumbers = utils::generateRandomNumbers(1000000, -10000, +10000);
}
// The buffers are needed later for better test case comparisons
std::cout << "Preparing buffers..." << std::endl;
std::vector<int> sortedNumbers;
std::vector<int> reversedNumbers;
sortedNumbers = originalNumbers;
std::sort(sortedNumbers.begin(), sortedNumbers.end());
reversedNumbers = sortedNumbers;
std::reverse(reversedNumbers.begin(), reversedNumbers.end());
assert(utils::isSorted(&(originalNumbers[0]), originalNumbers.size()) >= 0);
assert(utils::isSorted(&(sortedNumbers[0]), sortedNumbers.size()) == -1);
assert(utils::isReverseSorted(&(reversedNumbers[0]), reversedNumbers.size()) == -1);
// Holder for time measurements:
double stdSort[3] = { 0 };
double quickSort[3] = { 0 };
double stdNthElementSort[3] = { 0 };
double medianOfMedianRes[3] = { 0 };
double stdNthElement[3] = { 0 };
double nthElement[3] = { 0 };
std::vector<int> numbers;
// ========================================================================================================================================================================
// stdSort: unsorted array
std::cout << "Running std::sort on unsorted array..." << std::endl;
numbers = originalNumbers;
monitor.start();
std::sort(numbers.begin(), numbers.end());
stdSort[0] = monitor.stop();
utils::checkSortResult(numbers);
// stdSort: sorted array
std::cout << "Running std::sort on sorted array..." << std::endl;
numbers = sortedNumbers;
monitor.start();
std::sort(numbers.begin(), numbers.end());
stdSort[1] = monitor.stop();
utils::checkSortResult(numbers);
// stdSort: reverse sorted array
std::cout << "Running std::sort on reverse sorted array..." << std::endl;
numbers = reversedNumbers;
monitor.start();
std::sort(numbers.begin(), numbers.end());
stdSort[2] = monitor.stop();
utils::checkSortResult(numbers);
// ========================================================================================================================================================================
// quickSort: unsorted array
std::cout << "Running quickSort on unsorted array..." << std::endl;
numbers = originalNumbers;
monitor.start();
utils::quickSort(&(numbers[0]), numbers.size());
quickSort[0] = monitor.stop();
utils::checkSortResult(numbers);
// quickSort: sorted array
std::cout << "Running quickSort on sorted array..." << std::endl;
numbers = sortedNumbers;
monitor.start();
utils::quickSort(&(numbers[0]), numbers.size());
quickSort[1] = monitor.stop();
utils::checkSortResult(numbers);
// quickSort: reverse sorted array
std::cout << "Running quickSort on reverse sorted array..." << std::endl;
numbers = reversedNumbers;
monitor.start();
utils::quickSort(&(numbers[0]), numbers.size());
quickSort[2] = monitor.stop();
utils::checkSortResult(numbers);
// ========================================================================================================================================================================
// sort with std::nth_element
// std::nth_element: unsorted array
std::cout << "Running std::nth_element sort on unsorted array..." << std::endl;
numbers = originalNumbers;
monitor.start();
simon::std_nthElementSort(numbers, 0, numbers.size() / 2, numbers.size());
stdNthElementSort[0] = monitor.stop();
utils::checkSortResult(numbers);
// std::nth_element: sorted array
std::cout << "Running std::nth_element sort on sorted array..." << std::endl;
numbers = sortedNumbers;
monitor.start();
simon::std_nthElementSort(numbers, 0, numbers.size() / 2, numbers.size());
stdNthElementSort[1] = monitor.stop();
utils::checkSortResult(numbers);
// std::nth_element: reverse sorted array
std::cout << "Running std::nth_element sort on reverse sorted array..." << std::endl;
numbers = reversedNumbers;
monitor.start();
simon::std_nthElementSort(numbers, 0, numbers.size() / 2, numbers.size());
stdNthElementSort[2] = monitor.stop();
utils::checkSortResult(numbers);
// ========================================================================================================================================================================
// median of medians: unsorted array
std::cout << "Running median of medians on unsorted array..." << std::endl;
numbers = originalNumbers;
monitor.start();
int median = simon::findMedianOfMedians(numbers, 0, numbers.size());
std::cout << "Median: " << median << std::endl;
medianOfMedianRes[0] = monitor.stop();
// median of medians: sorted array
std::cout << "Running median of medians on sorted array..." << std::endl;
numbers = sortedNumbers;
monitor.start();
median = simon::findMedianOfMedians(numbers, 0, numbers.size());
std::cout << "Median: " << median << std::endl;
medianOfMedianRes[1] = monitor.stop();
// median of medians: reverse sorted array
std::cout << "Running median of medians on reverse sorted array..." << std::endl;
numbers = reversedNumbers;
monitor.start();
median = simon::findMedianOfMedians(numbers, 0, numbers.size());
std::cout << "Median: " << median << std::endl;
medianOfMedianRes[2] = monitor.stop();
// ========================================================================================================================================================================
const int sampleCount = 100; // number of nth-element calls
int n = originalNumbers.size() / 2;
// std::nth_element: unsorted array
std::cout << "Running std::nth_element on unsorted array..." << std::endl;
numbers = originalNumbers;
for (int i = 0; i < sampleCount; ++i) {
//int n = utils::randRange(1, numbers.size());
monitor.start();
std::nth_element(numbers.begin(), numbers.begin() + n, numbers.end());
stdNthElement[0] += monitor.stop();
median = numbers[n];
}
std::cout << "Median: " << median << std::endl;
// std::nth_element: sorted array
std::cout << "Running std::nth_element on sorted array..." << std::endl;
numbers = sortedNumbers;
for (int i = 0; i < sampleCount; ++i) {
//int n = utils::randRange(1, numbers.size());
monitor.start();
std::nth_element(numbers.begin(), numbers.begin() + n, numbers.end());
stdNthElement[1] += monitor.stop();
median = numbers[n];
}
std::cout << "Median: " << median << std::endl;
// std::nth_element: reverse sorted array
std::cout << "Running std::nth_element on reverse sorted array..." << std::endl;
numbers = reversedNumbers;
for (int i = 0; i < sampleCount; ++i) {
//int n = utils::randRange(1, numbers.size());
monitor.start();
std::nth_element(numbers.begin(), numbers.begin() + n, numbers.end());
stdNthElement[2] += monitor.stop();
median = numbers[n];
}
std::cout << "Median: " << median << std::endl;
// ========================================================================================================================================================================
// nthElement: unsorted array
std::cout << "Running nthElement on unsorted array..." << std::endl;
numbers = originalNumbers;
for (int i = 0; i < sampleCount; ++i) {
//int n = utils::randRange(1, numbers.size());
monitor.start();
median = utils::nthElement(&(numbers[0]), numbers.size(), n);
nthElement[0] += monitor.stop();
}
std::cout << "Median: " << median << std::endl;
// nthElement: sorted array
std::cout << "Running nthElement on sorted array..." << std::endl;
numbers = sortedNumbers;
for (int i = 0; i < sampleCount; ++i) {
//int n = utils::randRange(1, numbers.size());
monitor.start();
median = utils::nthElement(&(numbers[0]), numbers.size(), n);
nthElement[1] += monitor.stop();
}
std::cout << "Median: " << median << std::endl;
// nthElement: reverse sorted array
std::reverse(numbers.begin(), numbers.end());
std::cout << "Running nthElement on reverse sorted array..." << std::endl;
numbers = reversedNumbers;
for (int i = 0; i < sampleCount; ++i) {
//int n = utils::randRange(1, numbers.size());
monitor.start();
median = utils::nthElement(&(numbers[0]), numbers.size(), n);
nthElement[2] += monitor.stop();
}
std::cout << "Median: " << median << std::endl;
// ========================================================================================================================================================================
std::cout << std::endl << numbers.size() << " elements have been used." << std::endl
<< " unsorted array sorted array reverse sorted array" << std::endl
<< "--------------------------------------------------------------------------------" << std::endl
<< " std::sort " << PerformanceMonitor::millisToString(stdSort[0]) << " " << PerformanceMonitor::millisToString(stdSort[1]) << " " << PerformanceMonitor::millisToString(stdSort[2]) << std::endl
<< " quicksort " << PerformanceMonitor::millisToString(quickSort[0]) << " " << PerformanceMonitor::millisToString(quickSort[1]) << " " << PerformanceMonitor::millisToString(quickSort[2]) << std::endl
<< " std::nthElementSort " << PerformanceMonitor::millisToString(stdNthElementSort[0]) << " " << PerformanceMonitor::millisToString(stdNthElementSort[1]) << " " << PerformanceMonitor::millisToString(stdNthElementSort[2]) << std::endl
<< " median of medians " << PerformanceMonitor::millisToString(medianOfMedianRes[0]) << " " << PerformanceMonitor::millisToString(medianOfMedianRes[1]) << " " << PerformanceMonitor::millisToString(medianOfMedianRes[2]) << std::endl
<< " std::nthElement " << PerformanceMonitor::millisToString(stdNthElement[0]) << " " << PerformanceMonitor::millisToString(stdNthElement[1]) << " " << PerformanceMonitor::millisToString(stdNthElement[2]) << std::endl
<< " nth-element " << PerformanceMonitor::millisToString(nthElement[0]) << " " << PerformanceMonitor::millisToString(nthElement[1]) << " " << PerformanceMonitor::millisToString(nthElement[2]) << std::endl;
std::cout << "Note: nth element has been executed " << sampleCount << " times per measurement." << std::endl;
int mid = numbers.size() / 2;
std::cout << "Median: Middle element has value " << sortedNumbers[mid] << std::endl;
std::cin.ignore();
}
