Question

我的函数应该在给定位置后插入新节点，或者如果位置是尾部，则将其插入尾部并使新节点尾部

它适用于在给定位置插入节点，但在尾部后插入时不起作用。当我运行代码插入后尾部我得到一个分段错误。任何帮助将不胜感激！

ListNode *insertAfter(ListNode *argNode, int value) {
        ListNode *newNode = new ListNode(value);
        if(argNode != tail){
          argNode->next = newNode;
        } else {
          tail->next = newNode;
          tail = newNode;
        }
        size++;
        return newNode;
 }

Answer 1

让链接列表在下面。

Node1 -> Node2 -> NULL
Tail=Node2

如果您将Node3插入到最后。

Tail->Next = Node3
Node3->Next = NULL
So, the result is
Node1->Node2->Node3-> NULL

没关系。但是，如果将Node3插入Node1之后的位置。

ArgNode(Node1)
prev: Node1->Node2->NULL
next: Node1->Node3->NULL. Node2->NULL.

问题是Node3的下一个位置缺失。

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


struct ListNode {
    int value ;
    ListNode *next ;
    ListNode(int v) { value=v; next=NULL; }
};
int size=0 ;
ListNode *head = NULL;
ListNode *tail=NULL ;

ListNode *insertAfter(ListNode *argNode, int value) {
    ListNode *newNode = new ListNode(value);
    if ( argNode==NULL ) {
        if ( head==NULL ) {
            // initialize first node.
            head = tail = newNode ;
            newNode->next=NULL ;
        } else {
            // insert first node 
            newNode->next = head ;
            head = newNode ;
        }
    }
    else if(argNode != tail){
        newNode->next = argNode->next;
        argNode->next = newNode;
    } else {
        tail->next = newNode;
        tail = newNode;
    }
    size++;
    return newNode;
}

void printList(ListNode *a) {
    while ( a!=NULL ) {
        printf("%d ", a->value) ;
        a=a->next ;
    }
    printf(" size=%d\n", size) ;
}


int main() {

    ListNode *n, *n3, *n2 ;

    head =insertAfter(NULL, 10) ;
    printList(head) ;
    n2 = insertAfter(tail, 20) ;
    printList(head) ;
    n3 = insertAfter(tail, 30) ;
    printList(head) ;
    n = insertAfter(tail, 40) ;
    printList(head) ;
    n = insertAfter(n3, 35) ;
    printList(head) ;
    n = insertAfter(n2, 25) ;
    printList(head) ;
    n = insertAfter(NULL, 5) ;
    printList(head) ;
    return 0 ;
}

输出就是这个。

10  size=1
10 20  size=2
10 20 30  size=3
10 20 30 40  size=4
10 20 30 35 40  size=5
10 20 25 30 35 40  size=6
5 10 20 25 30 35 40  size=7

Answer 2

在

{% load static from staticfiles %}


<!DOCTYPE html>
<html lang="en">

  <head>
    <style>
      body{
        background: url('{% static "img/new4.jpg" %}') no-repeat center fixed;
        - webkit- background: cover;
        - moz - background: cover;
        - o - background: cover;
              background-size: cover;
      }

      </style>


    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <meta name="description" content="">
    <meta name="author" content="">

    <title>Personality Leading.com</title>

    <!-- Bootstrap core CSS -->
    <link href="{% static 'vendor/bootstrap/css/bootstrap.min.css' %}" rel="stylesheet">
    <!-- <link rel="stylesheet" type="text/css" href="{% static 'vendor/bootstrap/css/Custom' %}"> -->
    <link rel="stylesheet" type="text/css" href="{% static 'vendor/bootstrap/css/Custom.css' %}">

    <!-- Custom fonts for this template -->
    <link href="{% static 'vendor/font-awesome/css/font-awesome.min.css' %}" rel="stylesheet" type="text/css">
    <link href='https://fonts.googleapis.com/css?family=Lora:400,700,400italic,700italic' rel='stylesheet' type='text/css'>
    <link href='https://fonts.googleapis.com/css?family=Open+Sans:300italic,400italic,600italic,700italic,800italic,400,300,600,700,800' rel='stylesheet' type='text/css'>

    <!-- Custom styles for this template -->
    <link href="{% static 'css/clean-blog.min.css' %}" rel="stylesheet">

  </head>

  <body>

<!-- Navigation -->
<div class="mynav">
  <div class="p-3 mb-2 bg-info text-white"><strong> PERSONALITY LEADING </strong></div>
  <nav class="navbar navbar-expand-lg navbar-light fixed-top" id="mainNav">
      <div class="container">
        <a class="navbar-brand" href="index.html"></a>
        <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarResponsive" aria-controls="navbarResponsive" aria-expanded="false" aria-label="Toggle navigation">
          Menu
          <i class="fa fa-bars"></i>
        </button>
        <div class="collapse navbar-collapse" id="navbarResponsive">
          <ul class="navbar-nav ml-auto">
            <li class="nav-item">
              <a class="nav-link" href="/home/">Home</a>
            </li>
            <li class="nav-item">
              <a class="nav-link" href="/about/">About</a>
            </li>
            <li class="nav-item">
              <a class="nav-link" href="/services/">Services</a>
            </li>
            <li class="nav-item">
              <a class="nav-link" href="/contact/">Contact</a>
            </li>
          </ul>
        </div>
      </div>
    </nav>
  </div>
</div>

    <br>
    <br>
    <br>
    <br>

插入argNode->next = newNode;之前

。如果不是，那么你就会破坏链表中的链，因为你忘了将argeNode-＆gt;下一个值附加到链中。

链接列表，尾部后插入节点

2 个答案: