Insertion Sort List

#include<iostream>
#include<new>
using namespace std;

//Definition for singly-linked list.
struct ListNode
{
int val;
ListNode *next;
ListNode(int x) : val(x), next(NULL) {}
};

class Solution
{
public:
ListNode *insertionSortList(ListNode *&head)
{
if(head==NULL)
return NULL;
ListNode *pre=head;
ListNode *p=head;
ListNode *q=head->next;
ListNode *tmp=NULL;
head->next=NULL;
while(q)
{
tmp=q->next;
q->next=NULL;
while(p)
{
if(q->val>p->val)
{
pre=p;
p=p->next;
}
else
{
if(p==head)
{
q->next=head;
head=q;
}
else
{
q->next=p;
pre->next=q;
}
break;
}
}
if(p==NULL)
pre->next=q;
//每一个元素插入完成之后都要将p和pre指向头结点，从头开始比较插入
p=pre=head;
q=tmp;
}
return head;
}
void createList(ListNode *&head)
{
ListNode *p=NULL;
int i=0;
int arr[10]= {3,4,1,4,6,3,7,2,1,10};
for(i=0; i<10; i++)
{
if(head==NULL)
{
head=new ListNode(arr[i]);
if(head==NULL)
return;
}
else
{
p=new ListNode(arr[i]);
p->next=head;
head=p;
}
}
}
};
int main()
{
Solution s;
ListNode *L=NULL;
s.createList(L);
ListNode *head=L;
while(head)
{
cout<<head->val<<" ";
head=head->next;
}
cout<<endl;
L=s.insertionSortList(L);
while(L)
{
cout<<L->val<<" ";
L=L->next;
}
}