PCLP2/lab09/02.cpp

#include <iostream>
#include <vector>
#include <string>
#include <random>
#include <ctime>
#include <chrono>
using namespace std;

string generateWord() {
	const string charset = "abcdefghijklmnopqrstuvwxyz";
	int length = rand() % 20 + 1;
	string res = "";
	for(int i=0; i<length; i++) {
		res += charset[rand() % 26];
	}
	return res;
}

class ListItem {
public:
	ListItem(string val) {
		this->val = val;
		next = NULL;
	}
	string val;
	ListItem* next;
};

class List {
private:
	ListItem* first;
	int cnt;
public:
	List() {
		first = NULL;
		cnt = 0;
	}
	ListItem* begin() {
		return first;
	}
	ListItem** beginPtr() {
		return &first;
	}
	void push_back(string val) {
		if(first == NULL) {
			first = new ListItem(val);
		}
		else {
			ListItem* i = first;
			while(i->next != NULL){
				i = i->next;
			}
			i->next = new ListItem(val);
		}
		cnt++;
	}
	void clear() {
		for(ListItem* i = first; i;) {
			ListItem* cur = i;
			i = i->next;
			delete cur;
		}
		first = NULL;
		cnt = 0;
	}
	int size() {
		return cnt;
	}

	static ListItem* getLast(ListItem* i) {
		while(i->next != NULL){
			i = i->next;
		}
		return i;
	}
};

void benchmarkSorts(List* v1, vector<string>* v2, int size);
void sort_quick_driver(vector<string>* v);
void sort_quick_driver(List* v);

int main() {
	ios::sync_with_stdio(false);
	srand(time(0));

    List v1;
    vector<string> v2;

	benchmarkSorts(&v1, &v2, 10);
	benchmarkSorts(&v1, &v2, 1000);
	benchmarkSorts(&v1, &v2, 10000);

	return 0;
}



void generateSample(List* v1, vector<string>* v2, int size) {
	v1->clear();
	v2->clear();
	cout<<"----- Sample size: "<<size<<"\n";
    for(int i=0; i<size; i++) {
		string w = generateWord();
		v1->push_back(w);
		v2->push_back(w);
    }
}
void benchmarkSorts(List* v1, vector<string>* v2, int size) {
	generateSample(v1, v2, size);

	chrono::high_resolution_clock::time_point v1t1 = chrono::high_resolution_clock::now();
	sort_quick_driver(v1);
	chrono::high_resolution_clock::time_point v1t2 = chrono::high_resolution_clock::now();
	int v1d = chrono::duration_cast<chrono::microseconds>(v1t2 - v1t1).count();
	cout<<"Quick sort time for list: "<<v1d<<" us\n";

	chrono::high_resolution_clock::time_point v2t1 = chrono::high_resolution_clock::now();
	sort_quick_driver(v2);
	chrono::high_resolution_clock::time_point v2t2 = chrono::high_resolution_clock::now();
	int v2d = chrono::duration_cast<chrono::microseconds>(v2t2 - v2t1).count();
	cout<<"Quick sort time for vector: "<<v2d<<" us\n";

	cout<<endl;
}

int sort_quick_partition(vector<string>* v, int low, int high) {
	string pivot = v->at(high);
	int i = low - 1;

	for(int j = low; j <= high - 1; j++) {
		if(v->at(j) < pivot) {
			i++;
			swap(v->at(i), v->at(j));
		}
	}
	swap(v->at(i+1), v->at(high));

	return i + 1;
}
void sort_quick(vector<string>* v, int low, int high) {
	if(low < high) {
		int parti = sort_quick_partition(v, low, high);

		sort_quick(v, low, parti - 1);
		sort_quick(v, parti + 1, high);
	}
}
void sort_quick_driver(vector<string>* v) {
    sort_quick(v, 0, v->size() - 1);
}

ListItem* sort_quick_partition(ListItem* low, ListItem* high, ListItem** newLow, ListItem** newHigh) {
	ListItem* pivot = high;
	ListItem* prev = NULL;
	ListItem* cur = low;
	ListItem* tail = pivot;

	while(cur != pivot) {
		if(cur->val < pivot->val) {
			if(*newLow == NULL) {
				*newLow = cur;
			}

			prev = cur;
			cur = cur->next;
		}
		else {
			if(prev) {
				prev->next = cur->next;
			}
			ListItem* tmp = cur->next;
			cur->next = NULL;
			tail->next = cur;
			tail = cur;
			cur = tmp;
		}
	}

	if(*newLow == NULL) {
		*newLow = pivot;
	}

	*newHigh = tail;

	return pivot;
}
ListItem* sort_quick(ListItem* low, ListItem* high) {
	if(!low || low == high) {
		return low;
	}

	ListItem* newLow = NULL;
	ListItem* newHigh = NULL;

	ListItem* pivot = sort_quick_partition(low, high, &newLow, &newHigh);

	if(newLow != pivot) {
		ListItem* tmp = newLow;
		while(tmp->next != pivot) {
			tmp = tmp->next;
		}
		tmp->next = NULL;

		newLow = sort_quick(newLow, tmp);
		tmp = List::getLast(newLow);
		tmp->next = pivot;
	}

	pivot->next = sort_quick(pivot->next, newHigh);

	return newLow;
}
void sort_quick_driver(List* v) {
	*v->beginPtr() = sort_quick(v->begin(), List::getLast(v->begin()));
}