【题目】
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
.
【题意】
给定一个链表和一个数值x,将链表中的值按x进行划分,小于x的在前,大于等于x的在后。两部分中节点的之间的相对位置与在原链表中时相同
【思路】
先将链表按x分裂成两个链表,一个链表中的值小于x, 另一个链表中的值大于等于x
然后在将两个链表链接起来。
【代码】
/** * 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) { if(head==NULL)return head; ListNode*headLess=NULL; ListNode*tailLess=NULL; ListNode*headGreater=NULL; ListNode*tailGreater=NULL; ListNode*pointer=head; while(pointer){ if(pointer->val<x){ if(tailLess==NULL)headLess=pointer; else tailLess->next=pointer; tailLess=pointer; pointer=pointer->next; tailLess->next=NULL; } else{ if(tailGreater==NULL)headGreater=pointer; else tailGreater->next=pointer; tailGreater=pointer; pointer=pointer->next; tailGreater->next=NULL; } } //合并两个链表 if(tailLess){ head=headLess; tailLess->next=headGreater; } else head=headGreater; return head; } };
LeetCode: Partition List [086],布布扣,bubuko.com
时间: 2024-08-05 23:40:41