【数据结构】05.双向链表

卡戎-caryon2024-07-07 14:20

一、双向链表的结构

注意：这里的"带头"跟前面我们说的"头节点"是两个概念，带头链表里的头节点，实际为"哨兵位"，哨兵位节点不存储任何有效元素，只是站在这里"放哨的"。

"哨兵位"存在的意义：遍历循环链表避免死循环。

二、双向链表的实现

2.1 双向链表结点的创建

c 复制代码 
typedef int DLType;
//创建结构体
typedef struct DList
{
	DLType data;
	struct DList* prev;
	struct DList* next;
}DL;

2.2 双向链表的初始化与销毁

c 复制代码 
//初始化phead
DL* init(void)
{
	DL* phead = BuyNewNode(0);
	return phead;
}
c 复制代码 
//销毁链表，这里需要主要phead是形参，这里的最后将phead置空并不能将原链表中的phead置空，
//因此原链表中的phead需要手动置空，详细实现见源码
void DLDesdroy(DL* phead)
{
	assert(phead);
	DL* tail =phead->next;
 
	while (tail != phead)
	{
		DL* next = tail->next;
		free(tail); 
		tail= next;
	}
	free(phead);
	phead = NULL;
}

2.3 双向链表的增删查改

由于多次创建结点，因此我们将它提炼为一个函数

c 复制代码 
//创造新的节点
DL* BuyNewNode(DLType  x)
{
	DL* newnode = (DL*)malloc(sizeof(DL));
	if (newnode == NULL)
	{
		perror("malloc is failed!\n");
		return 1;
	}
	newnode->data = x;
	newnode->next = newnode->prev = newnode;
	return newnode;
}
c 复制代码 
//尾插
void  DLPushBack(DL* phead,DLType x)
{
	assert(phead);
 
	DL* newnode = BuyNewNode(x);
 
	newnode->next = phead;
	phead->prev->next = newnode;
 
	newnode->prev = phead->prev;
	phead->prev = newnode;
}
 
 
//尾删
void DLPopBack(DL* phead)
{
	assert(phead);
	assert(phead->next != phead);
 
	DL* tail = phead->prev;
	DL* prev = tail->prev;
 
	prev->next = phead;
	phead->prev = prev;
	free(tail);
	tail = NULL;  
 
}
 
//头插
void DLPushFront(DL* phead, DLType x)
{
	assert(phead);
 
	DL* newnode = BuyNewNode(x);
 
	DL* first = phead->next;
 
	newnode->next = first;
	first->prev = newnode;
	phead->next = newnode;
	newnode->prev=phead;
}
 
//头删
void DLPopFront(DL* phead)
{
	assert(phead);
	assert(phead->next != phead);
 
	DL* first = phead->next;
	DL* second = first->next;
 
	phead->next = second;
	second->prev = phead;
 
	free(first);
	first = NULL;
}
 
 
//查找
DL* DLFind(DL* phead,DLType x)
{
	assert(phead);
 
	DL* cur = phead->next;
	while ( cur != phead)
	{
		if (cur->data == x)
		{
			return cur;
		}
		cur = cur->next;
	}
	return NULL;
}
 
 
 
//pos位置插入数据
void DLInsert(DL* pos,DLType x)
{
	assert(pos);
 
	DL* newnode = BuyNewNode(x);
	DL* prev = pos->prev;
    
	prev->next = newnode;
	newnode->prev = prev;
 
    newnode->next = pos;
	pos->prev = newnode;
}
 
//pos位置之后插入数据
void DLInsertAfter(DL* pos, DLType x)
{
	assert(pos);
 
	DL* newnode = BuyNewNode(x);
	DL* next = pos->next;
 
	newnode->next = next;
	next->prev = newnode;
	pos->next = newnode;
	newnode->prev = pos;
}
 
//删除pos位置元素
void  DLErase(DL* pos)
{
	assert(pos);
 
	DL* next = pos->next;
	DL* prev = pos->prev;
 
	prev->next = next;
	next->prev = prev;
 
	free(pos);
	pos = NULL;
}

2.4 双向链表的打印

c 复制代码 
//打印链表
void DLPrint(DL* phead)
{
	DL* pcur = phead->next;
	while (pcur != phead)
	{
		printf("%d->", pcur->data);
		pcur = pcur->next;
	}
	printf("NULL\n");
}

2.5 双向链表的源码

c 复制代码 
//DL.h
 
#pragma once
 
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
 
typedef int DLType;
 
typedef struct DList
{
	DLType data;
	struct DList* prev;
	struct DList* next;
}DL;
 
//初始化
DL* init(void);
//打印
void DLPrint(DL* phead);
 
//尾插、尾删
void  DLPushBack(DL* phead, DLType x);
void DLPopBack(DL* phead);
 
//头插、头删
void  DLPushFront(DL* phead, DLType x);
void  DLPopFront(DL* phead);
 
//查找
DL* DLFind(DL* phead, DLType x);
 
//指定位置插入数据、指定位置之后插入数据
void  DLInsert(DL* pos, DLType x);
void DLInsertAfter(DL* pos, DLType x);
 
//删除pos
void  DLErase(DL* phead);
 
void DLDesdroy(DL** phead);
c 复制代码 
//DL.c
#include "DList.h"
 
 
//创造新的节点
DL* BuyNewNode(DLType  x)
{
	DL* newnode = (DL*)malloc(sizeof(DL));
	if (newnode == NULL)
	{
		perror("malloc is failed!\n");
		return 1;
	}
	newnode->data = x;
	newnode->next = newnode->prev = newnode;
	return newnode;
}
 
 
//初始化phead
DL* init(void)
{
	DL* phead = BuyNewNode(0);
	return phead;
}
 
 
//打印链表
void DLPrint(DL* phead)
{
	DL* pcur = phead->next;
	while (pcur != phead)
	{
		printf("%d->", pcur->data);
		pcur = pcur->next;
	}
	printf("NULL\n");
}
 
 
//尾插
void  DLPushBack(DL* phead,DLType x)
{
	assert(phead);
 
	DL* newnode = BuyNewNode(x);
 
	newnode->next = phead;
	phead->prev->next = newnode;
 
	newnode->prev = phead->prev;
	phead->prev = newnode;
}
 
 
//尾删
void DLPopBack(DL* phead)
{
	assert(phead);
	assert(phead->next != phead);
 
	DL* tail = phead->prev;
	DL* prev = tail->prev;
 
	prev->next = phead;
	phead->prev = prev;
	free(tail);
	tail = NULL;  
 
}
 
//头插
void DLPushFront(DL* phead, DLType x)
{
	assert(phead);
 
	DL* newnode = BuyNewNode(x);
 
	DL* first = phead->next;
 
	newnode->next = first;
	first->prev = newnode;
	phead->next = newnode;
	newnode->prev=phead;
}
 
//头删
void DLPopFront(DL* phead)
{
	assert(phead);
	assert(phead->next != phead);
 
	DL* first = phead->next;
	DL* second = first->next;
 
	phead->next = second;
	second->prev = phead;
 
	free(first);
	first = NULL;
}
 
 
//查找
DL* DLFind(DL* phead,DLType x)
{
	assert(phead);
 
	DL* cur = phead->next;
	while ( cur != phead)
	{
		if (cur->data == x)
		{
			return cur;
		}
		cur = cur->next;
	}
	return NULL;
}
 
 
 
//pos位置插入数据
void DLInsert(DL* pos,DLType x)
{
	assert(pos);
 
	DL* newnode = BuyNewNode(x);
	DL* prev = pos->prev;
    
	prev->next = newnode;
	newnode->prev = prev;
 
    newnode->next = pos;
	pos->prev = newnode;
}
 
//pos位置之后插入数据
void DLInsertAfter(DL* pos, DLType x)
{
	assert(pos);
 
	DL* newnode = BuyNewNode(x);
	DL* next = pos->next;
 
	newnode->next = next;
	next->prev = newnode;
	pos->next = newnode;
	newnode->prev = pos;
}
 
//删除
void  DLErase(DL* pos)
{
	assert(pos);
 
	DL* next = pos->next;
	DL* prev = pos->prev;
 
	prev->next = next;
	next->prev = prev;
 
	free(pos);
	pos = NULL;
}
 
//销毁链表
void DLDesdroy(DL* phead)
{
	assert(phead);
	DL* tail =phead->next;
 
	while (tail != phead)
	{
		DL* next = tail->next;
		free(tail); 
		tail= next;
	}
	free(phead);
	phead = NULL;
}
相关推荐
我想进大厂28 分钟前
图论---朴素Prim（稠密图）
数据结构·c++·算法·图论
我想进大厂33 分钟前
图论---Bellman-Ford算法
数据结构·c++·算法·图论
lkbhua莱克瓦2444 分钟前
用C语言实现——一个中缀表达式的计算器。支持用户输入和动画演示过程。
c语言·开发语言·数据结构·链表·学习方法·交友·计算器
晓数1 小时前
【硬核干货】JetBrains AI Assistant 干货笔记
人工智能·笔记·jetbrains·ai assistant
我的golang之路果然有问题2 小时前
速成GO访问sql，个人笔记
经验分享·笔记·后端·sql·golang·go·database
lwewan2 小时前
26考研——存储系统（3）
c语言·笔记·考研
搞机小能手2 小时前
六个能够白嫖学习资料的网站
笔记·学习·分类
转基因3 小时前
Codeforces Round 1020 (Div. 3)(题解ABCDEF)
数据结构·c++·算法
nongcunqq3 小时前
爬虫练习 js 逆向
笔记·爬虫
汐汐咯3 小时前
终端运行java出现？？？
笔记
热门推荐
01KGG转MP3工具|非KGM文件|解密音频02从零安装 LLaMA-Factory 微调 Qwen 大模型成功及所有的坑03我决定放弃搞 Java 了04Coze扣子平台完整体验和实践（附国内和国际版对比）05YOLOv8入门 | 重要性能衡量指标、训练结果评价及分析及影响mAP的因素【发论文关注的指标】06DeepSeek各版本说明与优缺点分析07YOLOv5改进 | 添加CA注意力机制 + 增加预测层 + 更换损失函数之GIoU08苍穹外卖面试总结09yolov8，yolo11，yolo12 服务器训练到部署全流程 笔记10yolov8实战第五天——yolov8+ffmpg实时视频流检测并进行实时推流——（推流，保姆教学）