题解 | #反转链表#

/**
 * 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
 * @return ListNode类
 */
#include <math.h>
struct ListNode* ReverseList(struct ListNode* head ) {
    // write code here
    	if (!head) return head;
    struct ListNode* h = head;
    struct ListNode* b = NULL;
    struct ListNode* end = (struct ListNode*)malloc(sizeof(struct ListNode));
    end->next = NULL;
    end->val = head->val;
    if (h->next) {
    	h = h->next;
	} else {
		return end;
	}
    while (h) {
        b = (struct ListNode*)malloc(sizeof(struct ListNode));
        b->next = end;
        b->val = h->val;
        end = b;
        h = h->next;
    }
    return b;
}