1.链表
1.1 链表的概念及结构
概念:链表是一种物理存储结构上非连续、非顺序的存储结构,数据元素的逻辑顺序是通过链表 中的指针链接次序实现的 。
注意:
1.从上图可看出,链式结构在逻辑上是连续的。但是在物理上不一定连续
2.现实中的结点一般都是从堆上申请出来的
3.从堆上申请的空间,是按照一定的策略来分配的,两次申请的空间可能连续,也可能不连续
2 链表的实现
SList.h(头文件引用)
#pragma once
#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
#include <malloc.h>
#include <assert.h>
typedef int SLTDataType;
typedef struct SListNode
{
SLTDataType data;
struct SListNode* next;
}SLTNode;
void SLTPrint(SLTNode* phead);
SLTNode* BuySListNode(SLTDataType x);
void SLTPushBack(SLTNode ** pphead,SLTDataType x);
void SLTPushFront(SLTNode** pphead, SLTDataType x);
void SLTPopBack(SLTNode** pphead);
void SLTPopFront(SLTNode** pphead);
//作业
SLTNode* SLTFind(SLTNode* pphead,SLTDataType x);
//在pos之前插入x
void SLTInsert(SLTNode** pphead, SLTNode* pos, SLTDataType x);
//在之后插入x
void SLTInsertAfter( SLTNode* pos, SLTDataType x);
//删除pos位置
void SLTErase(SLTNode** pphead, SLTNode* pos);
//删除pos后一个位置
void SLTEraseAfter(SLTNode* phead,SLTNode* pos);
SList.c(函数功能的实现)
#include "SList.h"
void SLTPrint(SLTNode* phead)
{
SLTNode* cur = phead;
while (cur != NULL)
{
printf("%d->", cur->data);
cur = cur->next;
}
printf("NULL\n");
}
SLTNode* BuySListNode(SLTDataType x)
{
SLTNode* newnode = (SLTNode*)malloc(sizeof(SLTNode));
if (newnode == NULL)
{
perror("malloc fail");
exit(-1);
}
newnode->data = x;
newnode->next = NULL;
return newnode;
}
void SLTPushBack(SLTNode** pphead,SLTDataType x) //尾插
//需要用二级指针,结构体指针(地址),传递实参
{
assert(pphead); //空地址不正确
//assert(*pphead);//空链表可以尾插
SLTNode* newnode = BuySListNode(x);
if (*pphead == NULL) //如果为空,则指向新创建元素
{
*pphead = newnode;
}
else //不为空则遍历到尾部插入数据
{
//需要用指针结构体指针,改变结构体,传递形参
SLTNode* tail = *pphead;
while (tail->next != 0)
{
tail = tail->next;
}
tail->next = newnode;
}
}
void SLTPushFront(SLTNode** pphead, SLTDataType x)//头插
{
assert(pphead); //空地址不正确
assert(*pphead);//空链表不可以前删
SLTNode* newnode = BuySListNode(x);
newnode->next = *pphead;
*pphead = newnode;
}
void SLTPopBack(SLTNode** pphead) //尾删
{
// 1.空
assert(*pphead != NULL);
// 2.一个节点
if ((*pphead)->next == NULL)
{
free(*pphead);
*pphead = NULL;
}
// 3.多个节点
else
{
SLTNode* tail = *pphead;
while (tail->next->next)
{
tail = tail->next;
}
free(tail->next);
tail->next = NULL;
}
}
void SLTPopFront(SLTNode** pphead) //头删
{
assert(pphead);
assert(*pphead);
SLTNode* newhead = (*pphead)->next;
free(*pphead);
*pphead = newhead;
}
SLTNode* SLTFind(SLTNode*phead, SLTDataType x)
{
assert(phead);
SLTNode* tail = phead;
while (tail)
{
if (tail->data == x)
{
return tail;
}
tail = tail->next;
}
return NULL;
while (tail->data != x)
{
tail = tail->next;
if (tail->next==NULL&&tail->data!=x)
//下一个元素的值指向NULL并且数据值不等于要查找的数,既已遍历查找完毕并且没有找到数据
{
printf(" 输入错误,找不到输入值\n");
return 0;
}
}
printf("已找到:%d\n", x);
return tail;
}
void SLTInsert(SLTNode** pphead, SLTNode* pos, SLTDataType x)
{
//有错误版本 ,地址近似一样(bug)find函数调试就好了
assert(pos);
assert(*pphead);
if (pos == *pphead)
{
SLTPushFront(pphead, x);
}
else
{
SLTNode* tail = *pphead;
//在pos之前插入x
while (tail->next != pos)
{
tail = tail->next;
}
SLTNode* newnode = BuySListNode(x);
tail->next = newnode;
newnode->next = pos;
}
}
void SLTInsertAfter(SLTNode* pos, SLTDataType x)
{
assert(pos);
assert(pos->next);
SLTNode* newnode = BuySListNode(x);
//注意顺序,不然会照成死循环(画图)
newnode->next = pos->next;
pos->next = newnode;
}
void SLTErase(SLTNode** pphead, SLTNode* pos)
{
assert(pos);
if (pos == *pphead)
{
SLTPopFront(pphead);
}
else
{
SLTNode* prev = *pphead;
while (prev->next != pos)
{
prev = prev->next;
}
prev->next = pos->next;
free(pos);
}
}
void SLTEraseAfter(SLTNode* phead,SLTNode* pos)
{
//assert(pos);
//检查是否为尾节点
//assert(pos->next);
SLTNode* posNext; //纪录要删除的节点
//避免丢失无法Free
posNext = pos->next;
//pos->next = pos->next->next;
pos->next = posNext->next;
free(posNext);
posNext = NULL;
}
Test_1_16(各种功能的调试、函数、以及面试OJ题的接口实现)
#include "SList.h"
void TestSList1()
{
int n;
printf("请输入链表长度:");
scanf("%d", &n);
printf("\n请依次输入每个节点的值:");
SLTNode* plist = NULL; //第一个元素的地址
for (size_t i = 0; i < n; i++)
{
int val;
scanf("%d", &val);
SLTNode* newnode = BuySListNode(val);
//头插
newnode->next = plist;
plist = newnode;
}
SLTPrint(plist);
SLTPushBack(&plist, 5);
SLTPrint(plist);
}
void TestSList()
{
SLTNode* plist = NULL;
SLTPushBack(&plist, 1);
SLTPushBack(&plist, 2);
SLTPushBack(&plist, 3);
SLTPushBack(&plist, 4);
SLTPushBack(&plist, 5);
SLTPrint(plist);
SLTPushFront(&plist, 10);
SLTPushFront(&plist, 20);
SLTPushFront(&plist, 30);
SLTPushFront(&plist, 40);
SLTPrint(plist);
}
void TestSList3()
{
SLTNode* plist = NULL;
SLTPushBack(&plist, 1);
SLTPushBack(&plist, 2);
SLTPushBack(&plist, 3);
SLTPushBack(&plist, 4);
SLTPushBack(&plist, 5);
SLTPrint(plist);
SLTPopBack(&plist);
SLTPrint(plist);
SLTPopBack(&plist);
SLTPrint(plist);
SLTPopBack(&plist);
SLTPrint(plist);
SLTPopBack(&plist);
SLTPrint(plist);
SLTPopBack(&plist);
SLTPrint(plist);
SLTPopBack(&plist);
SLTPrint(plist);
}
void TestSList4()
{
SLTNode* plist = NULL;
SLTPushBack(&plist, 1);
SLTPushBack(&plist, 2);
SLTPushBack(&plist, 3);
SLTPushBack(&plist, 4);
SLTPushBack(&plist, 5);
SLTPrint(plist);
//SLTPopFront(&plist);
//SLTPopFront(&plist);
//SLTPrint(plist);
SLTFind(plist, 1);
SLTFind(plist, 2);
SLTFind(plist, 3);
SLTFind(plist, 4);
SLTFind(plist, 5);
SLTFind(plist, 0);
}
void TestSlist5()
{
SLTNode* plist = NULL;
SLTPushBack(&plist, 1);
SLTPushBack(&plist, 2);
SLTPushBack(&plist, 3);
SLTPushBack(&plist, 4);
SLTPushBack(&plist, 5);
SLTPrint(plist);
SLTNode* pos = SLTFind(plist,4);
if (pos)
pos->data = 20;
//在pos之前插入x
//SLTInsert(&plist, pos, 5);
SLTPrint(plist);
}
void TestSlist6()
{
SLTNode* plist = NULL;
SLTPushBack(&plist, 1);
SLTPushBack(&plist, 2);
SLTPushBack(&plist, 3);
SLTPushBack(&plist, 4);
SLTPushBack(&plist, 5);
SLTPrint(plist);
SLTNode* pos = SLTFind(plist, 4);
SLTInsert(&plist, pos, 90);
SLTPrint(plist);
}
void TestSlist7()
{
SLTNode* plist = NULL;
SLTPushBack(&plist, 1);
SLTPushBack(&plist, 2);
SLTPushBack(&plist, 3);
SLTPushBack(&plist, 4);
SLTPushBack(&plist, 5);
SLTPrint(plist);
SLTNode* pos = SLTFind(plist, 4);
SLTInsertAfter(pos, 90);
SLTPrint(plist);
}
void TestSlist8()
{
SLTNode* plist = NULL;
SLTPushBack(&plist, 1);
SLTPushBack(&plist, 2);
SLTPushBack(&plist, 3);
SLTPushBack(&plist, 4);
SLTPushBack(&plist, 5);
SLTPrint(plist);
SLTNode* pos = SLTFind(plist, 4);
SLTErase(&plist,pos);
SLTPrint(plist);
}
void TestSlist9()
{
SLTNode* plist = NULL;
SLTPushBack(&plist, 1);
SLTPushBack(&plist, 2);
SLTPushBack(&plist, 3);
SLTPushBack(&plist, 4);
SLTPushBack(&plist, 5);
SLTPrint(plist);
SLTNode* pos = SLTFind(plist, 4);
SLTEraseAfter(&plist, pos);
SLTPrint(plist);
}
struct SListNode* removeElement()
{
;
}
struct ListNode {
int val;
struct ListNode* next;
};
//
//struct ListNode* FindKthToTail(struct ListNode* pListHead, int k)
//{
// struct ListNode* first = pListHead;
// struct ListNode* tail = pListHead;
//
// while (first->next)
// {
// while (k>0&&first->next)
// {
// k--;
// first = first->next;
// }
// if (first->next==NULL)
// {
// return tail;
// }
// tail = tail->next;
// first = first->next;
// }
// //tail=tail->next;
// return tail->next;
//}
struct ListNode* FindKthToTail(struct ListNode* pListHead, int k)
{
if (pListHead == NULL)
{
return pListHead;
}
struct ListNode* first = pListHead;
struct ListNode* tail = pListHead;
while (first->next)
{
while (k > 0 && first->next)
{
k--;
first = first->next;
//if (first->next == NULL && k > 0)
//{
// return NULL;
//}
}
if (first->next == NULL&&k==1)
{
return tail;
}
else
{
return NULL;
}
tail = tail->next;
first = first->next;
}
//tail=tail->next;
return tail->next;
}
int main()
{
struct SListNode* n1 = (struct ListNode*)malloc(sizeof(struct SListNode));
struct SListNode* n2 = (struct ListNode*)malloc(sizeof(struct SListNode));
struct SListNode* n3 = (struct ListNode*)malloc(sizeof(struct SListNode));
struct SListNode* n4 = (struct ListNode*)malloc(sizeof(struct SListNode));
struct SListNode* n5 = (struct ListNode*)malloc(sizeof(struct SListNode));
n1->data = 1;
n2->data = 2;
n3->data = 3;
n4->data = 4;
n5->data = 5;
n1->next = n2;
n2->next = n3;
n3->next = n4;
n4->next = n5;
n5->next = NULL;
FindKthToTail(n1, 6);
//TestSList1();
//TestSList3();
//TestSlist5();
//TestSlist7();
//TestSlist8();
//TestSlist9();
/*struct SListNode* n1 = (struct ListNode*)malloc(sizeof(struct SListNode));
struct SListNode* n2 = (struct ListNode*)malloc(sizeof(struct SListNode));
struct SListNode* n3 = (struct ListNode*)malloc(sizeof(struct SListNode));
struct SListNode* n4 = (struct ListNode*)malloc(sizeof(struct SListNode));
n1->data = 7;
n2->data = 7;
n3->data = 7;
n4->data = 7;
n1->next = n2;
n2->next = n3;
n3->next = n4;
n4->next = NULL;
struct SListNode* head = removeElement(n1, 7);
return 0;*/
}
//
//
//
//
//int nums1[6] = { 1,2,3,0,0,0 };
//int nums1Size = 6;
//int m = 3;
//int nums2[3] = { 2,5,6 };
//int nums2Size = 3;
//int n = 3;
int nums1[1];
int m = 0;
int nums2[1] = {1};
int n = 1;
// int p1 = m - 1, p2 = n - 1;
// int tail = m + n - 1;
// int cur;
// while (p1 > -1 || p2 > -1)
// {
// if (p1 == -1)
// {
// cur = nums2[p2--];
// }
// else if (p2 == -1)
// {
// cur = nums1[p1--];
// }
// else if (nums1[p1] > nums2[p2])
// {
// cur = nums1[p1--];
// }
// else
// {
// cur = nums2[p2--];
// }
// nums1[tail--] = cur;
// }