2.2.3—单链表— Partition List

描述
Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater
than or equal to x.
You should preserve the original relative order of the nodes in each of the two partitions.

For example, Given 1->4->3->2->5->2 and x = 3, return 1->2->2->4->3->5.

#include<iostream>using namespace std;struct node{int data;node *next;};class mylist{node *head;public:mylist(){head = new node();head->next = NULL;}void CreateList(int a[], int n);void Display();friend void PartionList(mylist &list, int value);~mylist();};void mylist::CreateList(int a[], int n){node *p = head;for (int i = 0; i < n; i++){node *q = new node();q->data = a[i];p->next = q;p = q;}p->next = NULL;}void mylist::Display(){node *p = head->next;while (p){cout << p->data << " ";p = p->next;}cout << endl;}void PartionList(mylist &list, int value){node *pre = list.head;node *p = list.head->next;//===while (p){if (p->data < value){pre = pre->next;p = p->next;}else{break;}}//===while (p){node *temp = p;while (p&&p->data >= value)//注意先后顺序{temp = p;p = p->next;}if (p){temp->next = p->next;p->next = pre->next;pre->next = p;pre = p;p = temp;}}}mylist::~mylist(){node *p = head;while (head){head = p->next;delete p;p = head;}}int main(){//===const int n = 8;int a[n] = { 1, 4, 3, 2, 5, 2,8,6 };//代表417593mylist list;list.CreateList(a, n);list.Display();//===int value = 4;PartionList(list, value);list.Display();}