题解 | #反转链表#

struct ListNode* ReverseList(struct ListNode* pHead ) {
    struct ListNode *p1,*p2,*p3;
    if(pHead!=NULL)
    {
    p1=pHead;
    p2=(struct ListNode *)malloc(sizeof(struct ListNode));
        p2->val=p1->val;
        p2->next=p3;
        p3=p2;
    p1=pHead->next;

    while(p1!=NULL)
    { 

        p2=(struct ListNode *)malloc(sizeof(struct ListNode));
        p2->val=p1->val;
        p2->next=p3;
        p3=p2;
        p1=p1->next;
        if(p1==NULL)
            break;

    }
        return p3;
    }
    else
    return pHead;
    // write code here
}