代码还是写出来更容易记住

下面的尾插还是有点瑕疵的，每次都重新找了尾结点，导致插入变成o(n),可以用一个变量记录一下尾指针，这样就是o(1)插入，但基础练习效果到了，不太想优化了~

#include<stdio.h>
#include<stdlib.h>

/*
1. CreateEmptyList(Node** head):创建一个空链表
2. CreateList(DataType *addr, unsigned int n, Node** head)：根据给定的数组初始化链表 (此处数组事先设定为[0,1,2,3,4,5,6,7,8,9])
3. ListInsert(Node *head, unsigned int index, DataType e)：在链表给定的位置(0---N-1)插入元素
4. ListDelete(Node *head, unsigned int index, DataType* e)：删除链表给定位置的元素，将删除节点的值返回给e
5. DestroyList(Node *head)：销毁链表，释放内存
*/
typedef struct Node {
    int data;
    struct Node* next;
} Node;
typedef struct Node* LinkList;

int op[10001], da[10001];
int n, now = 1;


Node* CreateEmptyList() {
    Node *head;
    head = (Node*)malloc(sizeof(Node));
    head->next = NULL;
    return head;
}

int CreateEmptyList(Node** head)
{
    *head = (Node*)malloc(sizeof(Node));
    (*head)->next = NULL;
    return 1;
}

Node* CreateList(int *addr, unsigned int n) {
    Node *head = CreateEmptyList();
    Node *p = head;
    for(int i = 0; i <= n; i++) {
        p = p->next = (Node*)malloc(sizeof (Node)); //带头结点
        p->data = addr[i];
    }
    p->next = NULL;
    return head;
}

void ListInsert(Node *head, unsigned int index, int e) {
    Node *p1 = head, *p2;
    while(index--)p1 = p1->next;
    p2 = (Node*)malloc(sizeof(Node));
    p2->data = e;
    p2->next = p1->next;
    p1->next = p2;
}

void ListDelete(Node *head, unsigned int index, int &e) {
    Node *p = head;
    while(index--)p = p->next;
    e = p->next->data;
    p->next = p->next->next;
}

void DestroyList(Node *head) {
    Node *p1, *p2 = head;
    if(p2 == NULL)return;
    while(p2 != NULL) {
        p1 = p2;
        p2 = p2->next;
        free(p1);
    }
}

void print(Node* head) {
    Node *p = head->next;
    for(; p != NULL; p = p->next)
        printf("%d ", p->data);
    puts("");
}

int main() {
    scanf("%d", &n);
    int cnt = 0;
    for(int i = 0; i < n; i++) {
        scanf("%d", &op[i]);
        if(op[i] == 3 || op[i] == 4)cnt++;
    }

    for(int i = 1; i <= 2 * cnt; i++)scanf("%d", &da[i]);
    int addr[11] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    Node * head;
    int e;

    for(int i = 0; i < n; i++) {
        if(op[i] == 1)head = CreateEmptyList();
        if(op[i] == 2)head = CreateList(addr, 9);
        if(op[i] == 3)ListInsert(head, da[now], da[now + 1]), now += 2;
        if(op[i] == 4)ListDelete(head, da[now], e), now += 2;
        if(op[i] == 5)DestroyList(head), printf("%d\n", e);
        else print(head);
    }

    return 0;
}

#include<bits/stdc++.h>
using namespace std;

typedef struct Node {
    int data;
    struct Node *next;
} node, *linklist;

node* create() {
    node* head;
    head = (node*)malloc(sizeof (node));
    head->next = NULL;
    return head;
}

void head_insert(node* head, int x) {
    node* q = create();
    q->data = x;
    q->next  = head->next;
    head->next = q;
}

void tail_insert(node* head, int x) {
    node *r = head; //尾指针
    while(r->next != NULL)r = r->next;
    node*q = create();
    q->data = x;
    r->next = q;
    r = q;
}

void print(node* head) {
    node *p = head->next;
    for(; p; p = p->next)cout << p->data << ' ';
    cout << "\n";
}

void delete_by_key(node*head, int x) {
    node* pre = head, *p = head->next;

    while(p != NULL) {
        if(p->data == x) {
            node*q = p;
            p = p->next;
            pre->next = p;
            free(q);
        } else {
            pre = pre->next;
            p = p->next;
        }
    }

}

void insert(node*p,int x){
    node*q=create();
    q->data=x;
    q->next=p->next;
    p->next=q;
}

node* find(node*head,int x){
    node*p=head->next;
    while(p->data<=x&&p->next!=NULL)p=p->next;
    return p;
}

int main() {

    node* head = create();

    int n;
    cin >> n;
    for(int i = 0; i < n; i++) {
        int x;
        cin >> x;
        tail_insert(head, x);
    }
//    cout << "输入要删除的值：\n";
//    int k;
//    cin >> k;
//    delete_by_key(head, k);
//
//    print(head);
//    
//    cout<<"输入插入的数字：\n";
//    cin>>k;
//    node* t = find(head,k);
//    insert(t,k);
//  print(head);
    node *A=create(),*B=create(),*p=head->next;

    int cnt=1;
    for(;p;p=p->next){
        if(cnt&1){
            tail_insert(A,p->data);
        }else{
            head_insert(B,p->data);
        }
        cnt++;
    }

    print(A);
    print(B);

    return 0;
}