标签：des style blog color 使用 os io for
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.
思路：使用两个指针分别记录小于x部分的尾部和不小于x部分的尾部。若当前值小于x，则将其插到小于x部分的链表的尾部；否则，将其插入到不小于x部分的链表的尾部。
1 class Solution { 2 public: 3 ListNode *partition( ListNode *head, int x ) { 4 if( !head || !head->next ) { return head; } 5 ListNode *prev = 0, *post = head; 6 while( post && post->val < x ) { 7 prev = post; 8 post = post->next; 9 } 10 while( post && post->next ) { 11 if( post->next->val < x ) { 12 ListNode *tmp = post->next; 13 post->next = tmp->next; 14 if( prev ) { 15 tmp->next = prev->next; 16 prev->next = tmp; 17 prev = tmp; 18 } else { 19 tmp->next = head; 20 head = prev = tmp; 21 } 22 } else { 23 post = post->next; 24 } 25 } 26 return head; 27 } 28 };
标签：des style blog color 使用 os io for
原文地址：http://www.cnblogs.com/moderate-fish/p/3925835.html
