22.2.04【学习记录】链表(单链表)

链表和数组是两个基本的数据结构，两者各有各的优点。

数组：

1.时间复杂度为O(1)的指定位置查找，例如想找到数组中第四个元素，直接数组名[3]就可以找到。

2.时间复杂度为O(n)对数组成员进行增添和删减。

链表：

1.时间复杂度为O(1)对数组成员进行增添和删减。

2.时间复杂度为O(n)的指定位置查找。

链表的概念：

链表其实就像一个绳子连着两个物体一样，然后一直连下去。

链表的创建：

typedef struct Node
{
	int date;
	struct Node* next;
}Node;

首先得创建一个头结点，起码知道起始点才能进行下面的操作嘛。

Node* headNode = (Node*)malloc(sizeof(Node));

然后创建链表,date为链表的长度：

void createList(Node* headNode, int date)
{
	Node* rear = headNode;
	for (int i = 0; i < date; i++)
	{
		Node* NewNode = (Node*)malloc(sizeof(Node));//创建一个新结点
		NewNode->next = NULL;
		scanf_s("%d", &NewNode->date);
		rear->next = NewNode;
		rear = NewNode;
	}
}

链表的遍历：

创建完后，遍历就很容易了：

void traveList(Node* headNode)
{
	Node* Move = headNode->next;
	while (Move)
	{
		printf("%d ", Move->date);
		Move = Move->next;
	}
	cout << endl;
}

接下来放在一个完整的代码里：
 

#include<iostream>
#include<stdlib.h>

using namespace std;

typedef struct Node
{
	int date;
	struct Node* next;
}Node;

void createList(Node* headNode, int date)
{
	Node* rear = headNode;
	for (int i = 0; i < date; i++)
	{
		Node* NewNode = (Node*)malloc(sizeof(Node));
		NewNode->next = NULL;
		scanf_s("%d", &NewNode->date);
		rear->next = NewNode;
		rear = NewNode;
	}
}

void traveList(Node* headNode)
{
	Node* Move = headNode->next;
	while (Move)
	{
		printf("%d ", Move->date);
		Move = Move->next;
	}
	cout << endl;
}

void insertForward(Node* headNode, int date)
{
	Node* NewNode = (Node*)malloc(sizeof(Node));
	NewNode->next = NULL;
	NewNode->date = date;
	NewNode->next = headNode->next;
	headNode->next = NewNode;
}

void insertBack(Node* headNode, int date)
{
	Node* NewNode = (Node*)malloc(sizeof(Node));
	NewNode->date = date;
	NewNode->next = NULL;
	Node* Move = headNode;
	while (Move->next)
	{
		Move = Move->next;
	}
	Move->next = NewNode;
}

void insertzj(Node* headNode, int weizhi, int date)
{
	int a = 0;
	Node* NewNode = (Node*)malloc(sizeof(Node));
	NewNode->next = NULL;
	NewNode->date = date;
	Node* Move1 = headNode;
	Node* Move2 = headNode->next;
	while (a != weizhi)
	{
		Move1 = Move1->next;
		Move2 = Move2->next;
		a++;
	}
	NewNode->next = Move2;
	Move1->next = NewNode;
}

void reverseList(Node* headNode)
{
	Node* hou = NULL;
	Node* qian = NULL;
	while (headNode->next)
	{
		hou = headNode->next;
		headNode->next = hou->next;
		hou->next = qian;
		qian = hou;
	}
	headNode->next = qian;
}

void deleteSame(Node* head) {
	Node* curr = head->next;
	while (curr) {
		Node* pre = curr;
		Node* p = curr->next;
		while (p) {
			if (curr->date == p->date)
			{
				pre->next = p->next;
				free(p);
				p = pre->next;
			}
			else 
			{
				pre = pre->next;
				p = p->next;
			}
		}
		curr = curr->next;
	}
}
int main()
{
	Node* headNode = (Node*)malloc(sizeof(Node));
	headNode->next = NULL;
	createList(headNode, 10);//链表的创建
	traveList(headNode);//链表的遍历
	insertForward(headNode, 100);//头插法
	traveList(headNode);
	insertBack(headNode, 200);//尾插法
	traveList(headNode);
	insertzj(headNode, 2, 300);//从中间插入法
	traveList(headNode);
	reverseList(headNode);//翻转链表
	traveList(headNode);
	deleteSame(headNode);//删除链表中相同的元素
	traveList(headNode);
	return 0;
}