86. 分隔链表

/**
 * 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) 
    {
       
        ListNode* min = new ListNode(0);
        ListNode* max = new ListNode(0);
        ListNode* minhead = min;
        ListNode* maxhead = max;

        while(head!=nullptr)
        {
            if(head->val < x)
            {
                min->next = head;
                min = min->next;
            }
            else{
                max->next = head;
                max = max->next;
            }
            head = head->next;
        }

        max->next = nullptr;
        min->next = maxhead->next;

        return minhead->next; 
    }
};