链表的两道小练习-链表翻转与链表中间值

1->链表的翻转

typedef struct List{
    int val;
    List * next;
}LinkList;

reverse(LinkList *head)
{
    LinkList *temp = head->next;
    LinkList *pre = head;
    LinkList *next = head ->next->next;
    for(next != NULL) {
        temp ->next = pre;
        pre = temp;
        temp = next;
        next = next->next;
    }
    temp ->next = pre;
    return temp;    
}

2->链表找中间节点

typedef struct node_t{
    int value;
    node_t *next;
}*LinkList;

void middle_node(LinkList * head){
    LinkList doubleStep = head;
    LinkList step = head;
    while(doubleStep != NULL) {
        doubleStep = doubleStep->next->next;
        step = step ->next;
    }
    return step;
}