mirror of https://github.com/TheAlgorithms/C
feat: add Circular Doubly Linked List implementation (#1038)
* Create circular_doubly_linked_list.c * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update circular_doubly_linked_list.c Added brief description of library files * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update circular_doubly_linked_list.c Done the all suggested changes. * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update circular_doubly_linked_list.c * updating DIRECTORY.md * updating DIRECTORY.md * updating DIRECTORY.md * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * There was typo while calling delete_first_node ! * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: David Leal <halfpacho@gmail.com> * updating DIRECTORY.md * Suggested changes are done. Done the suggested changes in functions 1. delete_first_node() 2. delete_last_node() * updating DIRECTORY.md * updating DIRECTORY.md * Worked on Suggested Changes * Suggested changes are done. * Update circular_doubly_linked_list.c Worked on all the suggested changes. Co-Authored-By: David Leal <halfpacho@gmail.com> Co-Authored-By: CascadingCascade <122662061+CascadingCascade@users.noreply.github.com> Co-Authored-By: Taj <tjgurwara99@users.noreply.github.com> * updating DIRECTORY.md * updating DIRECTORY.md * Worked on suggested changes for test cases. Check the code's functionality [here](https://leetcode.com/playground/WcRBMWa8) Co-Authored-By: CascadingCascade <122662061+CascadingCascade@users.noreply.github.com> * updating DIRECTORY.md * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: CascadingCascade <122662061+CascadingCascade@users.noreply.github.com> * Update circular_doubly_linked_list.c Update: Worked on suggested changes. * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: CascadingCascade <122662061+CascadingCascade@users.noreply.github.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: CascadingCascade <122662061+CascadingCascade@users.noreply.github.com> * Update data_structures/linked_list/circular_doubly_linked_list.c Co-authored-by: CascadingCascade <122662061+CascadingCascade@users.noreply.github.com> * Worked on suggested changes. * Minor upgrade. * updating DIRECTORY.md --------- Co-authored-by: David Leal <halfpacho@gmail.com> Co-authored-by: github-actions[bot] <github-actions@users.noreply.github.com> Co-authored-by: CascadingCascade <122662061+CascadingCascade@users.noreply.github.com> Co-authored-by: Taj <tjgurwara99@users.noreply.github.com>
This commit is contained in:
Sahil Kandhare
GitHub
parent
1cfb88c5eb
commit
f141ae4166
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@ -86,6 +86,7 @@
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* [Min Heap](https://github.com/TheAlgorithms/C/blob/HEAD/data_structures/heap/min_heap.c)
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* Linked List
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* [Ascending Priority Queue](https://github.com/TheAlgorithms/C/blob/HEAD/data_structures/linked_list/ascending_priority_queue.c)
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* [Circular Doubly Linked List](https://github.com/TheAlgorithms/C/blob/HEAD/data_structures/linked_list/circular_doubly_linked_list.c)
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* [Circular Linked List](https://github.com/TheAlgorithms/C/blob/HEAD/data_structures/linked_list/circular_linked_list.c)
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* [Doubly Linked List](https://github.com/TheAlgorithms/C/blob/HEAD/data_structures/linked_list/doubly_linked_list.c)
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* [Merge Linked Lists](https://github.com/TheAlgorithms/C/blob/HEAD/data_structures/linked_list/merge_linked_lists.c)
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@ -0,0 +1,304 @@
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/**
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* @file
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*
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* @details
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* Circular [Doubly Linked
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* List](https://en.wikipedia.org/wiki/Doubly_linked_list) combines the
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* properties of a doubly linked list and a circular linked list in which two
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* consecutive elements are linked or connected by the previous. Next, the
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* pointer and the last node point to the first node via the next pointer, and
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* the first node points to the last node via the previous pointer.
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*
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* In this implementation, functions to insert at the head, insert at the last
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* index, delete the first node, delete the last node, display list, and get
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* list size functions are coded.
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*
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* @author [Sahil Kandhare](https://github.com/SahilK-027)
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*
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*/
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#include <assert.h> /// to verify assumptions made by the program and print a diagnostic message if this assumption is false.
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#include <inttypes.h> /// to provide a set of integer types with universally consistent definitions that are operating system-independent
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#include <stdio.h> /// for IO operations
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#include <stdlib.h> /// for including functions involving memory allocation such as `malloc`
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/**
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* @brief Circular Doubly linked list struct
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*/
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typedef struct node
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{
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struct node *prev, *next; ///< List pointers
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uint64_t value; ///< Data stored on each node
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} ListNode;
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/**
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* @brief Create a list node
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* @param data the data that the node initialises with
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* @return ListNode* pointer to the newly created list node
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*/
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ListNode *create_node(uint64_t data)
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{
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ListNode *new_list = (ListNode *)malloc(sizeof(ListNode));
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new_list->value = data;
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new_list->next = new_list;
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new_list->prev = new_list;
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return new_list;
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}
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/**
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* @brief Insert a node at start of list
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* @param head start pointer of list
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* @param data the data that the node initialises with
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* @return ListNode* pointer to the newly created list node
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* inserted at the head
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*/
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ListNode *insert_at_head(ListNode *head, uint64_t data)
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{
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if (head == NULL)
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{
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head = create_node(data);
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return head;
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}
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else
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{
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ListNode *temp;
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ListNode *new_node = create_node(data);
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temp = head->prev;
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new_node->next = head;
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head->prev = new_node;
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new_node->prev = temp;
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temp->next = new_node;
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head = new_node;
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return head;
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}
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}
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/**
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* @brief Insert a node at end of list
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*
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* @param head start pointer of list
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* @param data the data that the node initialises with
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* @return ListNode* pointer to the newly added list node that was
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* inserted at the head of list.
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*/
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ListNode *insert_at_tail(ListNode *head, uint64_t data)
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{
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if (head == NULL)
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{
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head = create_node(data);
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return head;
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}
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else
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{
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ListNode *temp1, *temp2;
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ListNode *new_node = create_node(data);
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temp1 = head;
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temp2 = head->prev;
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new_node->prev = temp2;
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new_node->next = temp1;
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temp1->prev = new_node;
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temp2->next = new_node;
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return head;
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}
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}
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/**
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* @brief Function for deletion of the first node in list
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*
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* @param head start pointer of list
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* @return ListNode* pointer to the list node after deleting first node
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*/
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ListNode *delete_from_head(ListNode *head)
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{
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if (head == NULL)
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{
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printf("The list is empty\n");
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return head;
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}
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ListNode *temp1, *temp2;
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temp1 = head;
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temp2 = temp1->prev;
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if (temp1 == temp2)
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{
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free(temp2);
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head = NULL;
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return head;
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}
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temp2->next = temp1->next;
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(temp1->next)->prev = temp2;
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head = temp1->next;
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free(temp1);
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return head;
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}
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/**
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* @brief Function for deletion of the last node in list
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*
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* @param head start pointer of list
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* @return ListNode* pointer to the list node after deleting first node
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*/
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ListNode *delete_from_tail(ListNode *head)
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{
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if (head == NULL)
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{
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printf("The list is empty\n");
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return head;
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}
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ListNode *temp1, *temp2;
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temp1 = head;
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temp2 = temp1->prev;
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if (temp1 == temp2)
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{
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free(temp2);
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head = NULL;
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return head;
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}
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(temp2->prev)->next = temp1;
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temp1->prev = temp2->prev;
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free(temp2);
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return head;
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}
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/**
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* @brief The function that will return current size of list
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*
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* @param head start pointer of list
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* @return int size of list
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*/
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int getsize(ListNode *head)
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{
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if (!head)
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{
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return 0;
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}
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int size = 1;
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ListNode *temp = head->next;
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while (temp != head)
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{
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temp = temp->next;
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size++;
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}
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return size;
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}
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/**
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* @brief Display list function
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* @param head start pointer of list
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* @returns void
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*/
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void display_list(ListNode *head)
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{
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printf("\nContents of your linked list: ");
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ListNode *temp;
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temp = head;
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if (head != NULL)
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{
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while (temp->next != head)
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{
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printf("%" PRIu64 " <-> ", temp->value);
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temp = temp->next;
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}
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if (temp->next == head)
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{
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printf("%" PRIu64, temp->value);
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}
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}
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else
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{
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printf("The list is empty");
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}
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printf("\n");
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}
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/**
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* @brief access the list by index
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* @param list pointer to the target list
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* @param index access location
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* @returns the value at the specified index,
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* wrapping around if the index is larger than the size of the target
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* list
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*/
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uint64_t get(ListNode *list, const int index)
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{
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if (list == NULL || index < 0)
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{
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exit(EXIT_FAILURE);
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}
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ListNode *temp = list;
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for (int i = 0; i < index; ++i)
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{
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temp = temp->next;
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}
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return temp->value;
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}
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/**
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* @brief Self-test implementations
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* @returns void
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*/
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static void test()
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{
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ListNode *testList = NULL;
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unsigned int array[] = {2, 3, 4, 5, 6};
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assert(getsize(testList) == 0);
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printf("Testing inserting elements:\n");
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for (int i = 0; i < 5; ++i)
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{
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display_list(testList);
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testList = insert_at_head(testList, array[i]);
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assert(testList->value == array[i]);
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assert(getsize(testList) == i + 1);
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}
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printf("\nTesting removing elements:\n");
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for (int i = 4; i > -1; --i)
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{
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display_list(testList);
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assert(testList->value == array[i]);
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testList = delete_from_head(testList);
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assert(getsize(testList) == i);
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}
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printf("\nTesting inserting at tail:\n");
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for (int i = 0; i < 5; ++i)
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{
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display_list(testList);
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testList = insert_at_tail(testList, array[i]);
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assert(get(testList, i) == array[i]);
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assert(getsize(testList) == i + 1);
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}
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printf("\nTesting removing from tail:\n");
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for (int i = 4; i > -1; --i)
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{
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display_list(testList);
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testList = delete_from_tail(testList);
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assert(getsize(testList) == i);
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// If list is not empty, assert that accessing the just removed element
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// will wrap around to the list head
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if (testList != NULL)
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{
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assert(get(testList, i) == testList->value);
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}
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else
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{
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// If the list is empty, assert that the elements were removed after
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// the correct number of iterations
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assert(i == 0);
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}
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}
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}
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/**
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* @brief Main function
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* @returns 0 on exit
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*/
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int main()
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{
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test(); // run self-test implementations
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return 0;
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}
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