题解 | #单链表的排序#

利用最小堆

用 priority_queue 创建最小堆，遍历原链表，将每个结点的值 push 到最小堆中，然后再将堆顶元素依次弹出并创建新链表。

/**
 * struct ListNode {
 *    int val;
 *    struct ListNode *next;
 * };
 */

class Solution {
public:
    /**
     *
     * @param head ListNode类 the head node
     * @return ListNode类
     */
    ListNode* sortInList(ListNode* head) {
        // write code here
        priority_queue<int, vector<int>, greater<int>> pq;
        while (head) {
            pq.push(head->val);
            head = head->next;
        }
        ListNode* dummy = new ListNode(-1);
        ListNode* cur = dummy;
        while (!pq.empty()) {
            ListNode* new_head = new ListNode(pq.top());
            cur->next = new_head;
            cur = cur->next;
            pq.pop();
        }
        return dummy->next;
    }
};