标签：des style blog io ar color 使用 sp 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.
类似于款速排序中的分割算法。
因为是链表，不能使用从两头向中间扫描，而应使用从前向后扫描，详见算法导论 快速排序。
1 ListNode *partition(ListNode *head, int x) 2 { 5 ListNode *dummy = new ListNode(INT_MIN), *p, *q, *r; 6 dummy->next = head; 7 8 p = dummy; 9 q = dummy; 10 while (q->next != NULL) 11 { 12 if (q->next->val < x) 13 { 14 if (p == q) 15 { 16 p = p->next; 17 q = q->next; 18 continue; 19 } 20 r = q->next; 21 q->next = r->next; 22 r->next = p->next; 23 p->next = r; 24 p = r; 25 } 26 else 27 { 28 q = q->next; 29 } 30 } 31 32 p = dummy->next; 33 delete dummy; 34 return p; 35 }
标签：des style blog io ar color 使用 sp for
原文地址：http://www.cnblogs.com/ym65536/p/4148032.html
