b. Write a linked list implementation of self-adjusting lists. by c language

自调整列表（Adaptive Array List），也称为动态数组，是一种数据结构，它结合了链表和数组的优点，能自动调整存储容量以适应元素的增删。在C语言中，我们可以创建一个简单的双向链表实现自调整列表：

#include <stdlib.h>

typedef struct Node {
    int data;
    struct Node* prev;
    struct Node* next;
} Node;

typedef struct AdaptiveList {
    Node* head;
    Node* tail;
    int size;
    int capacity;
} AdaptiveList;

// 初始化列表
AdaptiveList* init_list() {
    AdaptiveList* list = (AdaptiveList*)malloc(sizeof(AdaptiveList));
    list->head = NULL;
    list->tail = NULL;
    list->size = 0;
    list->capacity = 4; // 初始容量
    return list;
}

// 插入元素到列表尾部
void insert(AdaptiveList* list, int value) {
    if ((list->size + 1) >= list->capacity) {
        resize_list(list); // 自动扩容
    }
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->data = value;
    newNode->prev = list->tail;
    newNode->next = NULL;
    if (list->tail != NULL) {
        list->tail->next = newNode;
    } else {
        list->head = newNode;
    }
    list->tail = newNode;
    list->size++;
}

// 扩容函数
void resize_list(AdaptiveList* list) {
    list->capacity *= 2;
    Node* newTail = (Node*)malloc(sizeof(Node) * list->capacity);
    newTail->prev = list->tail;
    newTail->next = NULL;
    if (list->tail != NULL) {
        list->tail->next = newTail;
    } else {
        list->head = newTail;
    }
    list->tail = newTail;
}

// 删除指定位置的元素
void delete_at(AdaptiveList* list, int index) {
    if (index >= 0 && index < list->size) {
        if (index == 0) {
            if (list->head == list->tail) {
                free(list->head);
                list->head = NULL;
                list->tail = NULL;
            } else {
                list->head = list->head->next;
                list->head->prev = NULL;
            }
        } else {
            Node* current = list->head;
            for (int i = 0; i < index - 1; i++) {
                current = current->next;
            }
            current->next = current->next->next;
            if (current->next != NULL) {
                current->next->prev = current;
            }
        }
        list->size--;
    }
}

// 示例操作
void main_example(AdaptiveList* list) {
    init_list();
    insert(list, 1);
    insert(list, 2);
    delete_at(list, 0);
    printf("Size: %d, Capacity: %d\n", list->size, list->capacity);
}