题解 | #链表分割#

/*
struct ListNode {
    int val;
    struct ListNode *next;
    ListNode(int x) : val(x), next(NULL) {}
};*/
class Partition {
public:
    ListNode* partition(ListNode* pHead, int x) 
    {
        struct ListNode* newhead, *newtail,*oldhead, *oldtail;
        newhead = newtail = (struct ListNode*)malloc(sizeof(struct ListNode));
        oldhead = oldtail = (struct ListNode*)malloc(sizeof(struct ListNode));
        struct ListNode* cur = pHead;

        while(cur)
        {
            if(cur->val < x)
            {
                newtail->next = cur;
                newtail = cur;
                cur = cur->next;
            }
            else 
            {
                oldtail->next = cur;
                oldtail = cur;
                cur = cur->next;
            }

        }

        newtail->next = oldhead->next;
        oldtail->next = NULL;

        return newhead->next;
    }
};