125 lines
2.6 KiB
C
125 lines
2.6 KiB
C
// linked list
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include "linked_list.h"
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struct linkedList* createLinkedList() {
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struct linkedList *list = (struct linkedList*) malloc(sizeof(struct linkedList));
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list->head = NULL;
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return list;
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}
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//insert link at the first location
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void insertFirst(struct linkedList *list, int key, void *data) {
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//create a link
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struct node *link = (struct node*) malloc(sizeof(struct node));
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link->key = key;
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link->data = data;
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//point it to old first node
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link->next = list->head;
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//point first to new first node
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list->head = link;
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}
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//delete first item
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struct node* deleteFirst(struct linkedList *list) {
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if (list->head == NULL) {
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return NULL;
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}
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//save reference to first link
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struct node *tempLink = list->head;
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//mark next to first link as first
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list->head = list->head->next;
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//return the deleted link
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return tempLink;
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}
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//find a link with given key
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struct node* find(struct linkedList *list, int key) {
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//start from the first link
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struct node* current = list->head;
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//if list is empty
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if(list->head == NULL) {
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return NULL;
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}
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//navigate through list
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while(current->key != key) {
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//if it is last node
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if(current->next == NULL) {
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return NULL;
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} else {
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//go to next link
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current = current->next;
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}
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}
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//if data found, return the current Link
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return current;
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}
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//delete a link with given key
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struct node* deleteElement(struct linkedList *list, int key) {
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//start from the first link
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struct node* current = list->head;
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struct node* previous = NULL;
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//if list is empty
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if(list->head == NULL) {
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return NULL;
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}
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//navigate through list
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while(current->key != key) {
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//if it is last node
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if(current->next == NULL) {
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return NULL;
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} else {
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//store reference to current link
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previous = current;
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//move to next link
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current = current->next;
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}
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}
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//found a match, update the link
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if(current == list->head) {
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//change first to point to next link
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list->head = list->head->next;
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} else {
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//bypass the current link
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previous->next = current->next;
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}
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return current;
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}
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//is list empty
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bool isEmpty(struct linkedList *list) {
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return list->head == NULL;
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}
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int length(struct linkedList *list) {
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int length = 0;
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struct node *current;
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for(current = list->head; current != NULL; current = current->next) {
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length++;
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}
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return length;
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} |