链表插入排序-LintCode

#ifndef C173_H
#define C173_H
#include<iostream>
using namespace std;
class ListNode{
public:
int val;
ListNode *next;
ListNode(int val)
{
this->val = val;
this->next = NULL;
}
};
class Solution {
public:
/**
* @param head: The first node of linked list.
* @return: The head of linked list.
*/
ListNode *insertionSortList(ListNode *head) {
// write your code here
if (head == NULL)
return NULL;
ListNode *p = head;
ListNode *node =new ListNode(-1);
while (p != NULL)
{
ListNode *q = node;
if (p == head)
{
node->next = new ListNode(p->val);
}
else
{
ListNode *p1 = node->next;
while (p1!=NULL)
{
if (p->val >= p1->val)
{
if (p1->next == NULL)
{
p1->next = new ListNode(p->val);
break;
}
else
{
p1 = p1->next;
q = q->next;
}
}
else
{
ListNode *l = new ListNode(p->val);
l->next = q->next;
q->next = l;
break;
}
}
}
p = p->next;
}
return node->next;
}
};
#endif