单链表简单操作

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

struct node
{
    int val;
    node* next;
};
void print(node* head)
{
    for (node* p = head; p; p = p -> next)
        cout << p -> val << " ";
    cout << endl;
}
void remove_1(node* &a, node* &c) //删除当前节点a的后一个节点c
{
    a -> next = a -> next -> next;
    delete c;
}
void remove_2(node* &a) //删除头节点
{
    auto p = a;
    a = a -> next;
    delete p;
}
void remove_toll(node* &head, int c) //删除链表中元素为c的节点
{
    if (head == NULL) return;
    if (head -> val == c)
    {
        node* p = head;
        head = head -> next;
        delete p;
        remove_toll(head, c);
    }
    else remove_toll(head -> next, c);
}
void insert(node* &a, node* &b, node* &c) // a, b插入c
{
    c -> next = b;
    a -> next = c;
}
int main()
{
    node* head = new node(), *q = new node(), *h = new node();
    head -> val = 1, q -> val = 2, h -> val = 3;
    head -> next = q;
    insert(head, head -> next, h);
    print(head);
    // remove_1(head, head -> next);
    // print(head);
    // remove_2(head);
    // print(head);
    remove_toll(head, 1);
    print(head);
    return 0;
}

双链表的简单操作 (双向循环只需要将头指针等于尾指针)

#include <bits/stdc++.h>
using namespace std;
struct node
{
    int val;
    node *next, *prev;
};
void print(node* head)
{
    for (node* p = head; p; p = p -> next)
        cout << p -> val << " ";
    cout << endl;
}
void remove(node* &a) //删除a节点
{
    a -> prev -> next = a -> next;
    a -> next -> prev = a -> prev; //可以颠倒顺序
}
void insert(node* &a, node* &b, node* &c) // a, b插入c
{
    c -> next = b, c -> prev = a;
    b -> prev = c, a -> next = c; //往右是next, 左是prev
}
int main()
{
    node* head = new node(), *q = new node(), *tail = new node(), *h = new node(), *hh = new node();
    head -> next = tail, tail -> prev = head;
    q -> val = 1, h -> val = 2, hh -> val = 3;
    insert(head, head -> next, q);
    insert(q, q -> next, h);
    insert(h, h -> next, hh);
    print(head);
    remove(hh);
    print(head);
    return 0;
}