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Trygve 2024-03-10 13:16:20 +01:00
parent 2314cf70aa
commit 5a3aa29482
4 changed files with 36 additions and 203 deletions
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12
lab_3/sequences-int/queue.h Normal file
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@ -0,0 +1,12 @@
#ifndef QUEUE_H
#define QUEUE_H
namespace seq {
class Queue {
public:
virtual void enqueue(int element) = 0;
virtual int dequeue() = 0;
};
}
#endif

56
lab_3/sequences-int/sequence-test.cpp
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@ -3,6 +3,7 @@
#include <iostream>
#include "dynamic-array.h"
#include "queue.h"
#include "singly-linked-list.h"
#include "doubly-linked-list.h"
@ -11,52 +12,17 @@ namespace
/*
* run a simple test
*/
void test_sequence(seq::Sequence* sqn, int n, int m, std::ostream* os)
void test_sequence(seq::Queue* sqn, int n, int m, std::ostream* os)
{
assert((m > 0) && (n > m));
if(os) *os << "Push even numbers from 0 to " << 2*(n-1) << ".\n";
for(int i = 0; i < n; i++) sqn->push(2*i);
if(os) *os << "Overwrite element at index " << m/2 << " with 0.\n";
int& item = sqn->at(m/2);
item = 0;
if(os) *os << "\nSize of sequence: " << sqn->size() << ".\n";
if(os) *os << "Detaching " << m/2 << " elements from front:";
for(int i = 0; i < m/2; i++)
{
if(os) *os << " " << sqn->front();
sqn->pop_front();
}
if(os) *os << ".\nDetaching " << m/2 << " elements from back:";
for(int i = 0; i < m/2; i++)
{
if(os) *os << " " << sqn->back();
sqn->pop_back();
}
if(os) *os << ".\nSize of sequence: " << sqn->size() << ".\n";
if(os) *os << "\nElement at index " << (n-m)/3 << ": " << sqn->at((n-m)/3) << ".\n";
if(os) *os << "Element at index " << 2*(n-m)/3 << ": " << sqn->at(2*(n-m)/3) << ".\n";
if(os) *os << "\nInsert " << m << " at index " << 2*(n-m)/3 << ".\n";
sqn->insert_at(2*(n-m)/3, m);
if(os) *os << "Size of sequence: " << sqn->size() << ".\n";
if(os) *os << "\nDelete element at index " << (n-m)/3 << ".\n";
sqn->erase_at((n-m)/3);
if(os) *os << "Size of sequence: " << sqn->size() << ".\n";
if(os) *os << "Element at index " << 2*(n-m)/3 - 1 << ": " << sqn->at(2*(n-m)/3 - 1) << ".\n";
if(os) *os << "\nClearing.\n";
sqn->clear();
if(os) *os << "Size of sequence: " << sqn->size() << ".\n";
if(os) *os << "Enqueue even numbers from 0 to " << 2*(n-1) << ".\n";
for(int i = 0; i < n; i++) sqn->enqueue(2*i);
}
/*
* return time measurement in units of seconds
*/
float test_with_time_measurement(seq::Sequence* sqn, int iterations)
float test_with_time_measurement(seq::Queue* sqn, int iterations)
{
int sequence_length = 200001;
int deletions = 10;
@ -82,20 +48,20 @@ namespace
int main()
{
int iterations = 200;
/*
std::cout << "*** test with dynamic array ***\n";
seq::DynamicArray dyna;
float dyna_time = test_with_time_measurement(&dyna, iterations);
*/
std::cout << "\n\n*** test with singly linked list ***\n";
seq::SinglyLinkedList sll;
float sll_time = test_with_time_measurement(&sll, iterations);
/*
std::cout << "\n\n*** test with doubly linked list ***\n";
seq::DoublyLinkedList dll;
float dll_time = test_with_time_measurement(&dll, iterations);
std::cout << "\n\nRuntime for dynamic array:\t" << dyna_time << " s\n";
*/
//std::cout << "\n\nRuntime for dynamic array:\t" << dyna_time << " s\n";
std::cout << "Runtime for singly linked list:\t" << sll_time << " s\n";
std::cout << "Runtime for doubly linked list:\t" << dll_time << " s\n";
//std::cout << "Runtime for doubly linked list:\t" << dll_time << " s\n";
}

123
lab_3/sequences-int/singly-linked-list.cpp
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@ -1,4 +1,5 @@
#include "singly-linked-list.h"
#include <algorithm>
using namespace seq;
@ -10,131 +11,23 @@ size_t SinglyLinkedList::size() const
return count;
}
// return pointer to the node at position i, counting from 0
SinglyLinkedListNode* SinglyLinkedList::index(int i) const
{
SinglyLinkedListNode* n = this->head;
for(int k = 0; k < i; k++)
{
assert(n != nullptr);
n = n->get_next();
}
return n;
}
// add an item at the end of the list
void SinglyLinkedList::push_back(const int& pushed_item)
void SinglyLinkedList::enqueue(int value)
{
SinglyLinkedListNode* new_node = new SinglyLinkedListNode;
new_node->set_item(pushed_item);
new_node->set_item(value);
if(this->empty()) this->head = new_node;
else this->tail->set_next(new_node);
this->tail = new_node;
}
// add an item at the beginning of the list
void SinglyLinkedList::push_front(const int& pushed_item)
int SinglyLinkedList::dequeue()
{
SinglyLinkedListNode* new_node = new SinglyLinkedListNode;
new_node->set_item(pushed_item);
if(this->empty()) this->tail = new_node;
else new_node->set_next(this->head); // FIG BUG from previous version, which was "else new_node->set_next(this->head->get_next());"
this->head = new_node;
}
// remove the head node and item
void SinglyLinkedList::pop_front()
{
if(this->empty()) return; // nothing there to remove
if(this->empty()) return 0; // nothing there to remove
SinglyLinkedListNode* successor = this->head->get_next();
int result = this->head->item;
delete this->head;
this->head = successor; // successor of the previous head is the new head
if(this->head == nullptr) this->tail = nullptr; // catch special case: the list is now empty
}
// remove the tail node and item
// note: in a singly linked list, we need to walk step by step to the end!
void SinglyLinkedList::pop_back()
{
if(this->empty()) return; // nothing there to remove
// list only contains one element
if(this->head->get_next() == nullptr)
{
delete this->head;
this->head = nullptr;
this->tail = nullptr;
return;
}
/*
* walk through until "third" is nullptr, second is the last element, and first is the second-to-last
*/
SinglyLinkedListNode* first = this->head;
SinglyLinkedListNode* second = first->get_next();
SinglyLinkedListNode* third = second->get_next();
while(third != nullptr)
{
first = second;
second = third;
third = third->get_next();
}
/*
* remove "second"
*/
if(this->tail == second) this->tail = first;
first->set_next(nullptr);
delete second;
}
// insert an item at index i
void SinglyLinkedList::insert_at(int i, const int& inserted_item)
{
if(i == 0)
{
this->push_front(inserted_item);
return;
}
SinglyLinkedListNode* predecessor = this->index(i-1);
this->insert_successor_to(predecessor, inserted_item);
}
// remove the item at index i
void SinglyLinkedList::erase_at(int i)
{
if(i == 0)
{
this->pop_front();
return;
}
SinglyLinkedListNode* predecessor = this->index(i-1);
this->erase_successor_to(predecessor);
}
// insert an item after given node
void SinglyLinkedList::insert_successor_to(SinglyLinkedListNode* predecessor, const int& inserted_item)
{
SinglyLinkedListNode* new_node = new SinglyLinkedListNode;
new_node->set_item(inserted_item);
SinglyLinkedListNode* successor = predecessor->get_next();
predecessor->set_next(new_node);
new_node->set_next(successor);
if(!successor) this->tail = new_node;
}
// remove the item after given node
void SinglyLinkedList::erase_successor_to(SinglyLinkedListNode* predecessor)
{
SinglyLinkedListNode* erased_node = predecessor->get_next();
SinglyLinkedListNode* new_successor = erased_node->get_next();
predecessor->set_next(new_successor);
if(new_successor == nullptr) this->tail = predecessor;
delete erased_node;
}
return result;
}

48
lab_3/sequences-int/singly-linked-list.h
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@ -3,6 +3,7 @@
#include <cassert>
#include "sequence.h"
#include "queue.h"
namespace seq
{
@ -29,55 +30,16 @@ namespace seq
friend class SinglyLinkedList; // allow SinglyLinkedList to access private members
};
class SinglyLinkedList: public Sequence
class SinglyLinkedList: public Queue
{
public:
bool empty() const { return (this->head == nullptr); } // test whether the singly linked list is empty
size_t size() const; // return the size (number of items in the singly linked list)
// it is the caller's responsibility to ensure that the list is not empty when calling front() or back()!
int& front() { assert(this->head); return this->head->get_item(); } // return a reference to the first item
int& back() { assert(this->tail); return this->tail->get_item(); } // return a reference to the final item
void enqueue(int element);
int dequeue();
// return a reference to the item at position i of the list, counting from 0
// it is the caller's responsibility that the index is within range
int& at(int i) { return this->index(i)->get_item(); }
// return pointer to the head/tail node
SinglyLinkedListNode* begin() const { return this->head; }
SinglyLinkedListNode* end() const { return this->tail; }
// return pointer to the node at position i, counting from 0
SinglyLinkedListNode* index(int i) const;
/*
* accepts an additional item into the singly linked list;
* by default, this is done at the back end of the list
* call push_front(...) to push an element at the front
*
* the list takes ownership of the copy (but not of the original!)
*/
void push(const int& pushed_item) { this->push_back(pushed_item); }
void push_back(const int& pushed_item);
void push_front(const int& pushed_item);
/*
* removes an item from the list (front end by default)
* to do the same at the back, call pop_back()
*/
void pop() { this->pop_front(); }
void pop_front();
void pop_back();
void clear() { while(!this->empty()) this->pop(); } // remove all the items from the list
// it is the caller's responsibility that the index is within range
void insert_at(int i, const int& inserted_item); // insert an item at index i
void erase_at(int i); // remove the item at index i
// it is the caller's responsibility that the node is actually part of the list
void insert_successor_to(SinglyLinkedListNode* predecessor, const int& inserted_item); // insert an item after given node
void erase_successor_to(SinglyLinkedListNode* predecessor); // remove the item after given node
void clear() { while(!this->empty()) this->dequeue(); } // remove all the items from the list
~SinglyLinkedList() { this->clear(); }
private: