如何使用链表实现队列

数据结构与算法

链表实在是太简单了。队列只需要维护链表的最后一个节点指针和头节点指针。

class ListNode<T> {
    T t;
    ListNode<T> next;
    public ListNode(T t) {
        this.t = t;
    }
}
class MyQueue<T> {
    ListNode<T> tail;
    ListNode<T> head;
    public MyQueue() {
        head = null;
        tail = null;
    }
    public boolean add(T t) {
        if (t == null) {
            return false;
        }
        ListNode<T> node = new ListNode<>(t);
        if (tail == null) {
            tail = node;
            head = tail;
        } else {
            tail.next = node;
            tail = tail.next;
        }
        return true;
    }
    public T peek() {
        return head.t;
    }
    public T remove() {
        T t = head.t;
        head = head.next;
        return t;
    }
    public int size() {
        ListNode<T> p = head;
        int counter = 0;
        while (p != null) {
            counter++;
            p = p.next;
        }
        return counter;
    }
}