题解 | #牛的品种排序IV#

创建优先级队列，将每个节点放入优先级队列中，然后依次弹出每个节点组合成链表返回。

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 *	ListNode(int x) : val(x), next(nullptr) {}
 * };
 */
#include <queue>
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param head ListNode类 
     * @return ListNode类
     */
    ListNode* sortCowsIV(ListNode* head) {
        // write code here
        priority_queue<ListNode*, vector<ListNode*>, Compare> pri_queue;
        ListNode* current = head;
        while(current != nullptr) {
            pri_queue.push(current);
            current = current->next;
        }
        head = pri_queue.top();
        pri_queue.pop();
        current = head;
        while(pri_queue.size() != 0) {
            current->next = pri_queue.top();
            pri_queue.pop();
            current = current->next;
            if(pri_queue.size() == 0) {
                current->next = nullptr;
            }
        }
        return head;
    }

    struct Compare {
        bool operator()(ListNode* a, ListNode* b) {
            return a->val > b->val;
        }
    };
};