From 7fa3e5e626318e34dc61c9f258e34e3760324745 Mon Sep 17 00:00:00 2001
From: Mactavish <maczhanchao@yahoo.com>
Date: Mon, 1 May 2023 09:27:41 +0200
Subject: [PATCH] add solution to linked-list
---
exercises/linked-list/linked_list.c | 139 +++++++++++++++++++++++++---
1 file changed, 127 insertions(+), 12 deletions(-)
diff --git a/exercises/linked-list/linked_list.c b/exercises/linked-list/linked_list.c
index 8981740..054dc38 100644
--- a/exercises/linked-list/linked_list.c
+++ b/exercises/linked-list/linked_list.c
@@ -1,55 +1,170 @@
#include "linked_list.h"
+#include <errno.h>
+#include <stdlib.h>
+
+#define FAULT(ERRNO, ERR_CODE) \
+ errno = ERRNO; \
+ exit(ERR_CODE);
+
+#define FREE_NODE(NODE) \
+ if (NODE) { \
+ free(NODE); \
+ NODE = NULL; \
+ }
+
struct list_node {
- struct list_node *prev, *next;
- ll_data_t data;
+ struct list_node *prev, *next;
+ ll_data_t data;
};
struct list {
- struct list_node *first, *last;
+ struct list_node *first, *last;
};
struct list_node *create_node(ll_data_t data) {
- // TODO: implement create_node
+ struct list_node *node;
+ node = malloc(sizeof(struct list_node));
+ if (!node) {
+ FAULT(ENOMEM, EXIT_FAILURE);
+ }
+ node->data = data;
+ return node;
}
// constructs a new (empty) list
struct list *list_create(void) {
- // TODO: implement list_create
+ struct list *head = malloc(sizeof(struct list));
+ // create a dummy node, dummy node should not have any previous node
+ struct list_node *node = create_node(0);
+ head->first = node;
+ head->last = node;
+ node->prev = node->next = NULL;
+ return head;
}
// counts the items on a list
size_t list_count(const struct list *list) {
- // TODO: implement list_count
+ size_t count = 0;
+ if (list->first == list->last) {
+ return count;
+ }
+ struct list_node *dummy = list->first;
+ struct list_node *node = dummy->next;
+ while (node != dummy) {
+ node = node->next;
+ count++;
+ }
+ return count;
}
// inserts item at back of a list
void list_push(struct list *list, ll_data_t item_data) {
- // TODO: implement list_push
+ struct list_node *node = create_node(item_data);
+ // empty list with a dummy node
+ if (list->first == list->last) {
+ list->first->next = node;
+ list->last = node;
+ node->prev = node->next = list->first;
+ } else {
+ node->prev = list->last;
+ list->last->next = node;
+ node->next = list->first;
+ list->last = node;
+ }
}
// removes item from back of a list
ll_data_t list_pop(struct list *list) {
- // TODO: implement list_pop
+ // empty list with a dummy node
+ if (list->first == list->last) {
+ FAULT(EFAULT, EXIT_FAILURE);
+ }
+ struct list_node *last = list->last;
+ ll_data_t data = last->data;
+ list->last = last->prev;
+ last->prev->next = list->first;
+ FREE_NODE(last);
+ return data;
}
// inserts item at front of a list
void list_unshift(struct list *list, ll_data_t item_data) {
- // TODO: implement list_unshift
+ // empty list with a dummy node
+ if (list->first == list->last) {
+ list_push(list, item_data);
+ } else {
+ struct list_node *dummy = list->first, *node = create_node(item_data);
+ node->next = dummy->next;
+ node->prev = dummy;
+ dummy->next->prev = node;
+ dummy->next = node;
+ }
}
// removes item from front of a list
ll_data_t list_shift(struct list *list) {
- // TODO: implement list_shift
+ // empty list with a dummy node
+ if (list->first == list->last) {
+ FAULT(EFAULT, EXIT_FAILURE);
+ } else {
+ struct list_node *dummy = list->first, *node;
+ node = dummy->next;
+ ll_data_t data = node->data;
+ dummy->next = node->next;
+ // if there are more than one nodes
+ if (node->next->prev == node) {
+ node->next->prev = dummy;
+ } else {
+ list->last = list->first;
+ }
+ FREE_NODE(node);
+ return data;
+ }
}
// deletes a node that holds the matching data
void list_delete(struct list *list, ll_data_t data) {
- // TODO: implement list_delete
+ if (list->first == list->last) {
+ errno = EFAULT;
+ exit(EXIT_FAILURE);
+ } else {
+ struct list_node *dummy = list->first;
+ struct list_node *node = dummy->next;
+ while (node != dummy) {
+ if (node->data == data) {
+ break;
+ }
+ node = node->next;
+ }
+ if (node != dummy) {
+ node->prev->next = node->next;
+ node->next->prev = node->prev;
+ if (node == list->last) {
+ list->last = node->prev;
+ }
+ FREE_NODE(node);
+ }
+ }
}
// destroys an entire list
// list will be a dangling pointer after calling this method on it
void list_destroy(struct list *list) {
- // TODO: implement list_destroy
+ // empty list with a dummy node
+ if (list->first == list->last) {
+ FREE_NODE(list->last);
+ FREE_NODE(list);
+ } else {
+ struct list_node *dummy = list->first;
+ struct list_node *node = dummy->next, *next;
+ while (node != dummy) {
+ next = node->next;
+ FREE_NODE(node);
+ node = next;
+ }
+ FREE_NODE(dummy);
+ FREE_NODE(list);
+ }
}
+
--
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