链表学习

1.链表创建

链表节点结构创建

struct ListNode
{
	int val;
	ListNode *next;
	ListNode(int x):val(x),next(NULL){}
}；

利用迭代器创建链表

using vecIter = vector<int>::iterator;
ListNode *createLinkedList(vecIter beg, vecIter end)
{
    ListNode *head = beg == end ? NULL : new ListNode(*beg++);
    for (ListNode *cur = head; beg != end; cur = cur->next)
        cur->next = new ListNode(*beg++);
    return head;
}

利用列表初始化创建

ListNode *create_linkedlist(std::initializer_list<int> lst)
{
    auto iter = lst.begin();
    ListNode *head = lst.size() ? new ListNode(*iter++) : NULL;
    for (ListNode *cur = head; iter != lst.end(); cur = cur->next)
        cur->next = new ListNode(*iter++);
    return head;
}

打印（清除）链表

void printAndClear(ListNode *head)
{
    while (head)
    {
        std::cout << head->val;
        if (head->next) std::cout << "->";
        ListNode *del = head;
        head = head->next;
        delete del;
    }
    std::cout << std::endl;
}