leetcode 148排序链表
优先队列容器,使用小顶堆排序;timeO(nlogn) spaceO(n)
/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode* sortList(ListNode* head) { struct cmp{ bool operator()(ListNode* a, ListNode* b){ return a->val > b->val; } }; priority_queue<ListNode*,vector<ListNode*>,cmp> q; ListNode *pre,*cur,*ahead; ahead=pre=new ListNode(-1); while(head!=NULL){ q.push(head); head=head->next; } while(!q.empty()){ cur=q.top(); pre->next=cur; pre=cur; pre->next=NULL; q.pop(); } return ahead->next; } };