题解 | #牛群分隔#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 *	ListNode(int x) : val(x), next(nullptr) {}
 * };
 */
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 
     * @param x int整型 
     * @return ListNode类
     */
    ListNode* cow_partition(ListNode* head, int x) {
	  //将head链表拆分成两段链表，一个是小于x的，一个是大于等于x的，最后将两个链表连接起来即可
        ListNode* Small = new ListNode(0);
        ListNode* SmallHead = Small;
        ListNode* Large = new ListNode(0);
        ListNode* LargeHead = Large;
        while(head){
            if(head->val < x){
                Small->next = head;
                Small = Small->next;
            }else{
                Large->next = head;
                Large = Large->next;
            }
            head = head->next;
        }
        Large->next = nullptr;
        Small->next = LargeHead->next;
        return SmallHead->next;
    }
};