带头结点的单链表（ 冒泡排序 一次遍历求中间结点的值） 链表 就地反转 倒数第k个结点

Source Code:

#include <iostream>using namespace std;typedef struct student{int num;struct student *next;}node;node  *create(){//with head nodenode *head,*p,*s;//head -->head    p-->end   s -->middle node int num;head = new node[sizeof(struct student)];p=head;cin>>num;while(num!=-1){s = new node[sizeof(struct student)];s->num= num;p->next = s;p = s;cin>>num;}p->next = NULL;return head;}int print(node *l)//return the len of the linklist{node *p = l;int count = 0;p = p->next;while(p){cout<<p->num<<" ";p= p->next;count++;}cout<<endl;return count;}int GetLen(node *l){node *p = l;int count = 0;p = p->next;while(p){p= p->next;count++;}return count;}node *sort(node *l){//sort AESint len = GetLen(l);node *head = l;node *p;//move forwardint temp;for(int i = 0;i<len-1;i++){p = head->next;for(int j = 0;j<len-i-1;j++){if(p->num>p->next->num){temp = p->num;p->num = p->next->num;p->next->num = temp;}p = p->next;}}return head;}int GetCenterNode(node *l){//一次遍历求中间结点的值node *p2 = l;//two stepnode *p1 = l;//one stepwhile(1){p2 = p2->next->next;p1 = p1->next;if(p2->next == NULL)//len %2 ==0break;if(p2->next->next == NULL)//len %2 == 1{p1 = p1->next;break;}}return p1->num;}int main(){node *StudentLink = create();int len= GetLen(StudentLink);cout<<"len="<<len<<endl;node *Sorted_StudetLink = sort(StudentLink);// O(n) + O(n*n)cout<<"After sorting ..."<<endl;print(Sorted_StudetLink);cout<<"the list's center node data is "<<GetCenterNode(StudentLink)<<endl;//O(n)return 0;}

Result:

就地反转

ListNode* ReverseList(ListNode* pHead){    ListNode* pNode=pHead;//当前结点    ListNode* pPrev=NULL;//当前结点的前一个结点    while(pNode!=NULL)    {        ListNode* pNext=pNode->m_pNext;        pNode->m_pNext=pPrev;//当前结点指向前一个结点        pPrev=pNode;//pPrev和pNode往前移动。        pNode=pNext;//这里要使用前面保存下来的pNext，不能使用pNode->m_pNext    }    return pPrev;//返回反转链表头指针。}

倒数第k个结点：

注意程序的鲁棒性

ListNode* KthNodeFromEnd(ListNode* pHead,int k){    if(pHead==NULL||k==0)        return NULL;    ListNode* pNode=pHead;//当前结点    ListNode* pKthNode=pHead;//    while(k-1>0)    {        if(pNode->m_pNext!=NULL)        {            pNode=pNode->m_pNext;//让pNode先走k-1步            --k;        }        else            return NULL;    }    while(pNode->m_pNext!=NULL)    {        pNode=pNode->m_pNext;        pKthNode=pKthNode->m_pNext;    }    return pKthNode;}