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// 707. Design Linked List
#include "leetcode.h"
/*
* design your implementation of the linked list. you can choose to use a singly
* or doubly linked list. a node in a singly linked list should have two
* attributes: 'val' and 'next'. 'val' is the value of the current node, and
* 'next' is a pointing/reference to the next code. if you want to use the
* doubly linked list, you will need one more attribute 'prev' to indicate the
* previous node in the linked list. assume all nodes in the linked list are
* 0-indexed to indicate the previous node in the linked list. assume all nodes
* in the linked list are 0-indexed.
*/
typedef struct List {
int val;
struct List *next;
} MyLinkedList;
MyLinkedList *myLinkedListCreate() {
MyLinkedList *obj = (MyLinkedList *)malloc(sizeof(MyLinkedList));
obj->val = -1;
obj->next = NULL;
return obj;
}
int myLinkedListGet(MyLinkedList *obj, int index) {
obj = obj->next;
int cnt = 0;
while (obj) {
if (cnt == index)
return obj->val;
cnt++;
obj = obj->next;
}
return -1;
}
void myLinkedListAddAtHead(MyLinkedList *obj, int val) {
MyLinkedList *tmp = (MyLinkedList *)malloc(sizeof(MyLinkedList));
tmp->val = val;
tmp->next = obj->next;
obj->next = tmp;
}
void myLinkedListAddAtTail(MyLinkedList *obj, int val) {
while (obj && obj->next)
obj = obj->next;
MyLinkedList *tmp = (MyLinkedList *)malloc(sizeof(MyLinkedList));
tmp->val = val;
tmp->next = NULL;
obj->next = tmp;
}
void myLinkedListAddAtIndex(MyLinkedList *obj, int index, int val) {
int cnt = 0;
MyLinkedList *tmp = obj;
while (tmp) {
if (cnt == index) {
MyLinkedList *curr = (MyLinkedList *)malloc(sizeof(MyLinkedList));
curr->val = val;
curr->next = tmp->next;
tmp->next = curr;
break;
}
cnt++;
tmp = tmp->next;
}
}
void myLinkedListDeleteAtIndex(MyLinkedList *obj, int index) {
int cnt = 0;
MyLinkedList *curr = obj->next, *pre = obj;
while (curr) {
if (cnt == index) {
pre->next = curr->next;
free(curr);
return;
}
cnt++;
pre = curr;
curr = curr->next;
}
}
void myLinkedListFree(MyLinkedList *obj) {
while (obj) {
MyLinkedList *tmp = obj;
obj = obj->next;
free(tmp);
}
}
int main() {
MyLinkedList *obj = myLinkedListCreate();
myLinkedListAddAtHead(obj, 1);
myLinkedListAddAtTail(obj, 3);
myLinkedListAddAtIndex(obj, 1, 2);
printf("%d\n", myLinkedListGet(obj, 1)); // expect: 2
myLinkedListDeleteAtIndex(obj, 1);
printf("%d\n", myLinkedListGet(obj, 1)); // expect: 3
myLinkedListFree(obj);
}
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