Created
March 12, 2022 16:11
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o(1) based linked list implementation
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#include <stdio.h> | |
#include <stdlib.h> | |
struct list { | |
void *data; | |
struct list *next; | |
}; | |
static struct list *head, *last; | |
void list_init() | |
{ | |
head = last = NULL; | |
} | |
int list_add(void *data) | |
{ | |
struct list *new = calloc(1, sizeof(struct list)); | |
if (!new) { | |
return -1; | |
} | |
new->data = data; | |
if (!head) { | |
head = new; | |
last = new; | |
} else { | |
last->next = new; | |
last = new; | |
} | |
return 0; | |
} | |
int list_add_head(void *data) | |
{ | |
struct list *new = calloc(1, sizeof(struct list)); | |
if (!new) { | |
return -1; | |
} | |
new->data = data; | |
new->next = head; | |
head = new; | |
return 0; | |
} | |
int list_delete_node(void *data, void (*callback)(void *data)) | |
{ | |
struct list *elem = head; | |
int found = -1; | |
if (head->data == data) { | |
if (callback) | |
callback(head->data); | |
if (last == head) { | |
last = NULL; | |
} | |
head = head->next; | |
free(elem); | |
found = 0; | |
} else { | |
struct list *prev; | |
prev = head; | |
elem = head->next; | |
for (elem = head->next, prev = head; elem; prev = elem, elem = elem->next) { | |
if (elem->data == data) { | |
if (elem == last) { | |
last = prev; | |
prev->next = NULL; | |
} else { | |
prev->next = elem->next; | |
} | |
free(elem); | |
break; | |
found = 0; | |
} | |
} | |
} | |
return found; | |
} | |
int list_for_each(void (*callback)(void *data)) | |
{ | |
struct list *elem; | |
if (!callback) { | |
return -1; | |
} | |
for (elem = head; elem; elem = elem->next) { | |
callback(elem->data); | |
} | |
return 0; | |
} | |
void print(void *val) | |
{ | |
printf("%d ", *(int *)val); | |
} | |
int main() | |
{ | |
int elems[10] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; | |
int i; | |
for (i = 0; i < 10; i ++) { | |
list_add(&elems[i]); | |
} | |
list_for_each(print); | |
printf("\n"); | |
list_delete_node(&elems[1], NULL); | |
list_for_each(print); | |
printf("\n"); | |
list_delete_node(&elems[0], NULL); | |
list_for_each(print); | |
printf("\n"); | |
list_delete_node(&elems[9], NULL); | |
list_for_each(print); | |
printf("\n"); | |
int test[10]; | |
for (i = 0; i < 10; i ++) { | |
test[i] = elems[i]; | |
list_add(&test[i]); | |
} | |
list_for_each(print); | |
printf("\n"); | |
} |
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