数据结构—链表
2020-05-29 16:01:41来源:博客园 阅读 ()
数据结构—链表
3.1链表的定义
找了一堆感觉都是废话
3.2动态内存分配
malloc:
fp = (数据类型*)malloc(sizeof(数据类型))
free:
free(void *fp)
3.3链表的建立
typedef struct list
{
int num;
struct list *next;
}node;
typedef node *link;
?
link creat_list(int n)
{
link head;
link ptr;
int i;
?
head = (link)malloc(sizeof(node));
if(!head)
{
cout << "内存分配失败" << endl;
return 0;
}
head->next = NULL;
ptr = head;
?
cout << "输入n个数据" << endl;
for(i = 1; i <= n; ++i)
{
scanf("%d", &ptr->num);
ptr->next = (link)malloc(sizeof(node));
if(!ptr->next)
{
cout << "内存分配失败" << endl;
return 0;
}
ptr->next->next = NULL;
ptr = ptr->next;
}
return head;
}
3.4链表的遍历
link find_node(link head, int num)
{
link ptr;
ptr = head;
while (ptr != NULL)
{
if(ptr->num == num)
return ptr;
ptr = ptr->next;
}
cout << "node" << endl;
return ptr;
}
3.5链表的连接
link concatenate(link ptr1, link ptr2)
{
link ptr;
ptr = ptr1;
while(ptr->next != NULL) //让ptr1的尾巴指向ptr2的头
ptr = ptr->next;
ptr->next = ptr2;
return ptr1;
}
3.6链表内节点的删除
三种情况:
-
删除第一个节点
-
删除最后一个节点
-
删除中间节点
link delete_node(link head, link ptr)
{
link previous;
if(ptr == head) //删头
return head->next;
else
{
previous = head;
while (previous->next != ptr)
{
previous = previous->next;
}
previous->next = ptr->next;
}
free(ptr); //有借有还,再借不难
return head;
}
3.7释放链表的内存空间
link destroy_list(link head)
{
link ptr;
while(head != NULL)
{
ptr = head;
head = head->next;
free(ptr);
}
}
3.8链表内节点的插入
与删除一样会有三种情况
link insert_node(link head, link ptr, int value) //插入在ptr之后
{
link new_node = (link)malloc(sizeof(node));
if(!new_node)
{
cout << "分配内存失败" << endl;
return NULL;
}
new_node->num = value;
new_node->next = NULL;
if(ptr == NULL) //头插
{
new_node->next = head;
return new_node;
}
else
{
if(ptr->next == NULL) //尾插
ptr->next = new_node;
else //中间插
{
new_node->next = ptr->next;
ptr->next = new_node;
}
}
return head;
}
3.9链表结构的反转
link invert_list(link head)
{
link mid, last;
mid = NULL;
while(head != NULL)
{
last = mid;
mid = head;
head = head->next;
mid->next = last;
}
return mid;
}
让我们看看具体是怎么来的:
-
执行while之前 head指向链表第一个 mid == NULL, last无值
-
执行一次 head指向链表第二个 mid 指向 链表第一个 last == NULL
-
再执行一次 head指向链表第三个 mid 指向 链表第二个 last 指向 链表第一个 并且 mid的前驱是last
-
反复直到反转完成 返回mid 也就是反转后的头节点
3.10循环链表结构
头尾相连的链表
3.10.1首先建立链表
typedef struct clist
{
int data;
struct clist *next;
}cnode;
typedef cnode *clink;
?
clink creat_list(int n)
{
clink head;
clink ptr;
int i;
?
head = (clink)malloc(sizeof(cnode));
if(!head)
{
cout << "内存分配失败" << endl;
return 0;
}
head->next = NULL;
ptr = head;
?
cout << "输入n个数据" << endl;
for(i = 1; i <= n; ++i)
{
scanf("%d", &ptr->data);
ptr->next = (clink)malloc(sizeof(cnode));
if(!ptr->next)
{
cout << "内存分配失败" << endl;
return 0;
}
ptr->next->next = NULL;
ptr = ptr->next;
}
ptr->next = NULL;
return head;
}
3.10.2循环链表内节点的插入
-
情况一 :插在链表的头部成为链表的新开始
-
将新节点的指针指向链表的第一个节点
-
找到最后一个节点且将其指针指向新节点
-
返回新节点 为链表新头部
-
-
情况二:除情况一的其他情况,假设插在ptr之后
-
将新节点的指针指向ptr下一节点
-
将ptr的下一节点设为新节点
-
clink insert_node(clink head, clink ptr, int value)
{
clink new_node = (clink)malloc(sizeof(cnode));
clink previous;
if(!new_node)
{
cout << "分配内存失败" << endl;
return NULL;
}
new_node->data = value;
new_node->next = NULL;
if(head == NULL) //原先就是空表
{
new_node->next = new_node;
return new_node;
}
if(ptr == NULL) // 头插
{
new_node->next = head;
previous = head;
while(previous->next != NULL)
previous = previous->next;
previous->next = new_node;
head = new_node;
}
else
{
new_node->next = ptr->next;
ptr->next = new_node;
}
return head;
}
3.10.3循环链表内节点的删除
-
情况一:删第一个
-
将链表的开始移向下一节点
-
将最后一个节点指向第二个节点
-
-
情况二:除情况一的其他情况,删除ptr
-
找到ptr的前一个节点
-
将ptr前一个节点的后继设为ptr的后继
-
clink delete_node(clink head, clink ptr)
{
clink previous;
if(head == NULL) //空表
return NULL;
previous = head;
if(head != head->next) //不止一个节点
while(previous->next != ptr)
previous = previous->next;
?
if(ptr == head) //头插
{
head = head->next;
previous->next = ptr->next;
}
else
{
previous->next = ptr->next;
}
free(ptr);
return head;
}
3.11双向链表结构
3.11.1双向链表的建立
俩个指针,一个指向前驱,一个指向后继
typedef struct dlist
{
int data;
struct dlist *front; //后继
struct dlist *back; //前驱
}dnode;
typedef dnode *dlink;
?
dlink create_dlist(int *arr, int len)
{
dlink head, before, new_node;
int i;
head = (dlink)malloc(sizeof(dnode));
if(!head)
{
cout << "内存分配失败" << endl;
return NULL;
}
head->data = arr[0];
head->back = NULL;
head->front = NULL;
before = head;
for(i = 1; i < len; ++i)
{
new_node = (dlink)malloc(sizeof(dnode));
new_node->data = arr[i];
new_node->front = NULL;
new_node->back = before;
before = new_node;
}
return head;
}
3.11.2双向链表的插入
-
情况一:头插
-
将新节点的指针front指向双向链表的开始
-
将表头的back指向新节点
-
head = new_node
-
-
情况二:尾插
-
将最后一个节点的front指向新节点
-
新节点的back指向尾部
-
-
情况三:中间插,假设在ptr之后
-
新节点的前驱指向ptr
-
新节点的后继变为ptr的后继
-
ptr的后继指向新节点
-
原ptr后继的前驱指向新节点
-
dlink insert_node(dlink head, dlink ptr, int value)
{
dlink new_node = (dlink)malloc(sizeof(dnode));
if(!new_node)
{
cout << "内存分配失败" << endl;
return NULL;
}
new_node->back = NULL;
new_node->front = NULL;
new_node->data = value;
if(head == NULL) //空表
return new_node;
if(ptr == NULL) //头插
{
new_node->front = head;
head->back = new_node;
head = new_node;
}
else
{
if(ptr->front == NULL) //尾插
{
ptr->front = new_node;
new_node->back = ptr;
}
else
{
ptr->front->back = new_node;
new_node->front = ptr->front;
new_node->back = ptr;
ptr->front = new_node;
}
}
return head;
}
3.11.3双向链表节点的删除
-
情况一:删头
-
将指向链表开始节点的指针head指向第二个节点
-
将第二个节点的前驱设为NULL
-
-
情况二:删尾
-
最后一节点的后继设为NULL
-
-
情况三:删中间,删除ptr
-
ptr前驱的后继设为ptr后继的前驱
-
ptr后继的前驱设为ptr前驱的后继
-
dlink delete_node(dlink head, dlink ptr)
{
if(ptr->back == NULL) //删头
{
head = head->front;
head->back = NULL;
}
else
{
if(ptr->front == NULL) //删尾
{
ptr->back->front == NULL;
}
else
{
ptr->back->front = ptr->front;
ptr->front->back = ptr->back;
}
}
free(ptr);
return head;
}
3.12循环双向链表
3.12.1建立
typedef struct dlist
{
int data;
struct dlist *front; //后继
struct dlist *back; //前驱
}cdnode;
typedef cdnode *cdlink;
?
cdlink create_dlist(int *arr, int len)
{
cdlink head, before, new_node;
int i;
head = (cdlink)malloc(sizeof(cdnode));
if(!head)
{
cout << "内存分配失败" << endl;
return NULL;
}
head->data = arr[0];
head->back = NULL;
head->front = NULL;
before = head;
for(i = 1; i < len; ++i)
{
new_node = (cdlink)malloc(sizeof(cdnode));
new_node->data = arr[i];
new_node->front = NULL;
new_node->back = before;
before = new_node;
}
head->back = new_node;
new_node->front = head;
//head->back = NULL;
//new_node->front = NULL;
return head;
}
-
情况一:删除或插入第一个节点
-
情况二:除情况一
3.12.2删除
cdlink delete_node(cdlink head, cdlink ptr)
{
if(head == NULL)
return NULL;
if(ptr == head) head = head->front; //头
ptr->back->front = ptr->front;
ptr->front->back = ptr->back;
free(ptr);
return head;
}
3.12.3插入
cdlink insert_node(cdlink head, cdlink ptr, int value)
{
cdlink new_node = (cdlink)malloc(sizeof(cdnode));
if(!new_node)
{
cout << "内存分配失败" << endl;
return NULL;
}
new_node->data = value;
if(head == NULL) //空表
{
new_node->back = new_node;
new_node->front = new_node;
return new_node;
}
if(ptr == NULL) //头插
{
head->back->front = new_node;
new_node->front = head;
new_node->back = head->back;
head->back = new_node;
head = new_node;
}
else
{
ptr->front->back = new_node;
new_node->front = ptr->front;
new_node->back = ptr;
ptr->front = new_node;
}
return head;
}
最后代码大汇总
#include <bits/stdc++.h> using namespace std; typedef struct list { int num; struct list *next; }node; typedef node *link; link creat_list(int n) { link head; link ptr; int i; head = (link)malloc(sizeof(node)); if(!head) { cout << "内存分配失败" << endl; return 0; } head->next = NULL; ptr = head; cout << "输入n个数据" << endl; for(i = 1; i <= n; ++i) { scanf("%d", &ptr->num); ptr->next = (link)malloc(sizeof(node)); if(!ptr->next) { cout << "内存分配失败" << endl; return 0; } ptr->next->next = NULL; ptr = ptr->next; } return head; } link find_node(link head, int num) { link ptr; ptr = head; while (ptr != NULL) { if(ptr->num == num) return ptr; ptr = ptr->next; } cout << "node" << endl; return ptr; } link concatenate(link ptr1, link ptr2) { link ptr; ptr = ptr1; while(ptr->next != NULL) ptr = ptr->next; ptr->next = ptr2; return ptr1; } link delete_node(link head, link ptr) { link previous; if(ptr == head) return head->next; else { previous = head; while (previous->next != ptr) { previous = previous->next; } previous->next = ptr->next; } free(ptr); return head; } link destroy_list(link head) { link ptr; while(head != NULL) { ptr = head; head = head->next; free(ptr); } } link insert_node(link head, link ptr, int value) //插入在ptr之后 { link new_node = (link)malloc(sizeof(node)); if(!new_node) { cout << "分配内存失败" << endl; return NULL; } new_node->num = value; new_node->next = NULL; if(ptr == NULL) //头插 { new_node->next = head; return new_node; } else { if(ptr->next == NULL) //尾插 ptr->next = new_node; else //中间插 { new_node->next = ptr->next; ptr->next = new_node; } } return head; } link invert_list(link head) { link mid, last; mid = NULL; while(head != NULL) { last = mid; mid = head; head = head->next; mid->next = last; } return mid; } int main() { return 0; }
#include <bits/stdc++.h> using namespace std; typedef long long ll; typedef struct clist { int data; struct clist *next; }cnode; typedef cnode *clink; clink creat_list(int n) { clink head; clink ptr; int i; head = (clink)malloc(sizeof(cnode)); if(!head) { cout << "内存分配失败" << endl; return 0; } head->next = NULL; ptr = head; cout << "输入n个数据" << endl; for(i = 1; i <= n; ++i) { scanf("%d", &ptr->data); ptr->next = (clink)malloc(sizeof(cnode)); if(!ptr->next) { cout << "内存分配失败" << endl; return 0; } ptr->next->next = NULL; ptr = ptr->next; } ptr->next = NULL; //ptr->next = head; return head; } clink insert_node(clink head, clink ptr, int value) { clink new_node = (clink)malloc(sizeof(cnode)); clink previous; if(!new_node) { cout << "分配内存失败" << endl; return NULL; } new_node->data = value; new_node->next = NULL; if(head == NULL) //原先就是空表 { new_node->next = new_node; return new_node; } if(ptr == NULL) // 头插 { new_node->next = head; previous = head; while(previous->next != NULL) previous = previous->next; previous->next = new_node; head = new_node; } else { new_node->next = ptr->next; ptr->next = new_node; } return head; } clink delete_node(clink head, clink ptr) { clink previous; if(head == NULL) //空表 return NULL; previous = head; if(head != head->next) //不止一个节点 while(previous->next != ptr) previous = previous->next; if(ptr == head) //头插 { head = head->next; previous->next = ptr->next; } else { previous->next = ptr->next; } free(ptr); return head; } int main() { return 0; }
#include <bits/stdc++.h> using namespace std; typedef struct dlist { int data; struct dlist *front; //后继 struct dlist *back; //前驱 }dnode; typedef dnode *dlink; dlink create_dlist(int *arr, int len) { dlink head, before, new_node; int i; head = (dlink)malloc(sizeof(dnode)); if(!head) { cout << "内存分配失败" << endl; return NULL; } head->data = arr[0]; head->back = NULL; head->front = NULL; before = head; for(i = 1; i < len; ++i) { new_node = (dlink)malloc(sizeof(dnode)); new_node->data = arr[i]; new_node->front = NULL; new_node->back = before; before = new_node; } return head; } dlink insert_node(dlink head, dlink ptr, int value) { dlink new_node = (dlink)malloc(sizeof(dnode)); if(!new_node) { cout << "内存分配失败" << endl; return NULL; } new_node->back = NULL; new_node->front = NULL; new_node->data = value; if(head == NULL) //空表 return new_node; if(ptr == NULL) //头插 { new_node->front = head; head->back = new_node; head = new_node; } else { if(ptr->front == NULL) //尾插 { ptr->front = new_node; new_node->back = ptr; } else { ptr->front->back = new_node; new_node->front = ptr->front; new_node->back = ptr; ptr->front = new_node; } } return head; } dlink delete_node(dlink head, dlink ptr) { if(ptr->back == NULL) //删头 { head = head->front; head->back = NULL; } else { if(ptr->front == NULL) //删尾 { ptr->back->front == NULL; } else { ptr->back->front = ptr->front; ptr->front->back = ptr->back; } } free(ptr); return head; } int main() { return 0; }
#include <bits/stdc++.h> using namespace std; typedef struct dlist { int data; struct dlist *front; //后继 struct dlist *back; //前驱 }cdnode; typedef cdnode *cdlink; cdlink create_dlist(int *arr, int len) { cdlink head, before, new_node; int i; head = (cdlink)malloc(sizeof(cdnode)); if(!head) { cout << "内存分配失败" << endl; return NULL; } head->data = arr[0]; head->back = NULL; head->front = NULL; before = head; for(i = 1; i < len; ++i) { new_node = (cdlink)malloc(sizeof(cdnode)); new_node->data = arr[i]; new_node->front = NULL; new_node->back = before; before = new_node; } head->back = new_node; new_node->front = head; //head->back = NULL; //new_node->front = NULL; return head; } cdlink delete_node(cdlink head, cdlink ptr) { if(head == NULL) return NULL; if(ptr == head) head = head->front; //头 ptr->back->front = ptr->front; ptr->front->back = ptr->back; free(ptr); return head; } cdlink insert_node(cdlink head, cdlink ptr, int value) { cdlink new_node = (cdlink)malloc(sizeof(cdnode)); if(!new_node) { cout << "内存分配失败" << endl; return NULL; } new_node->data = value; if(head == NULL) //空表 { new_node->back = new_node; new_node->front = new_node; return new_node; } if(ptr == NULL) //头插 { head->back->front = new_node; new_node->front = head; new_node->back = head->back; head->back = new_node; head = new_node; } else { ptr->front->back = new_node; new_node->front = ptr->front; new_node->back = ptr; ptr->front = new_node; } return head; } int main() { return 0; }
原文链接:https://www.cnblogs.com/xiguan/p/12989587.html
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