题解 | #反转链表#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 *
 * C语言声明定义全局变量请加上static，防止重复定义
 *
 * C语言声明定义全局变量请加上static，防止重复定义
 */

/**
 * 
 * @param pHead ListNode类 
 * @return ListNode类
 */
struct ListNode* ReverseList(struct ListNode* pHead ) {
    if(pHead==NULL){
        return pHead;
    }
    struct ListNode* p= pHead;
    struct ListNode* pNext=p->next;
    p->next=NULL;
    struct ListNode* pForward=NULL;
    
    //核心代码
    while(pNext!=NULL){
        pForward=p;
        p=pNext;
        pNext=p->next;
        p->next=pForward;
    }
    
    p->next=pForward;
    pHead=p;
    return pHead;
}