Partition List 分割链表

/**

* Definition for singly-linked list.

* struct ListNode {

* int val;

* ListNode *next;

* ListNode(int x) : val(x), next(NULL) {}

* };

*/

class Solution {

public:

ListNode *partition(ListNode *head, int x) {

ListNode dummy1(-1);

ListNode dummy2(-1);

ListNode *prev1=&dummy1;

ListNode *prev2=&dummy2;

ListNode *curr=head;

while(curr!=NULL)

{

if(curr->val<x)

{

prev1->next=curr;

prev1=prev1->next;

}

else

{

prev2->next=curr;

prev2=prev2->next;

}

curr=curr->next;

}

prev1->next=NULL;

prev2->next=NULL;

if(dummy1.next==NULL) return dummy2.next;

else

{

prev1->next=dummy2.next;

return dummy1.next;

}

}

};