[LeetCode] Sort List

Sort a linked list in O(n log n) time using constant space complexity.

比较蛋疼，我取巧了。可能不合题意。

/** * 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) {        ListNode *p = head;        while(p)        {            list.push_back(p->val);            p = p->next;        }        sort(list.begin(), list.end());        head = build_list(list);        return head;    }    ListNode *build_list(vector<int> list)    {        ListNode *head = nullptr, *p = nullptr;        for(int i = 0; i < list.size(); i++)        {            ListNode *tmp = new ListNode(list[i]);            if(i == 0)            {                head = p = tmp;                continue;            }            p->next = tmp;            p = tmp;        }        return head;    }private:    vector<int> list;};