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  • 数据结构双向链表 DoublyLinkedList

    package datastructures.linked;
    
    import java.util.Iterator;
    
    /**
     * @author warriorg
     */
    public class DoublyLinkedList<T> implements Iterable<T> {
        private int size = 0;
        private Node<T> head = null;
        private Node<T> tail = null;
    
        class Node<T> {
            T data;
            Node<T> prev;
            Node<T> next;
    
            Node(T data, Node<T> prev, Node<T> next) {
                this.data = data;
                this.prev = prev;
                this.next = next;
            }
    
            @Override
            public String toString() {
                return "[" + prev + "|" + data + "|" + next + "]";
            } 
        }
    
        public T peek() {
            return head == null ? null : head.data;
        }
    
    
        public Boolean add(T item) {
            addLast(item); 
            return true; 
        }
    
        public void addFirst(T item) {
            final Node<T> first = head;
            final Node<T> node = new Node<>(item, null, head);
            head = node;
            if (first == null) {
                tail = node;
            } else {
                first.prev = node;
            }
            size++;
        }
    
        public void addLast(T item) {
            final Node<T> prev = tail; 
            final Node<T> node = new Node<>(item, prev, null);
            tail = node;
            if (prev == null) {
                head = node;
            } else {
                prev.next = node;
            }
            size++;
        }
    
        public void clear() {
            for (Node<T> curr = head; curr != null;) {
                Node<T> next = curr.next;
                curr.data = null;
                curr.prev = null;
                curr.next = null;
                curr = next;
            }
    
            head = tail = null;
            size = 0;
        }
    
        public T get(int index) {
            checkElementIndex(index);
    
            Node<T> curr = head;
            for (int i = 0; i < size; i++) {
                if (index == i) {
                    return curr.data;
                }
                curr = curr.next;            
            }
            return null;
        }
    
        public boolean remove(T item) {
            return true;
        }
    
        public int size() {
            return size;
        }
    
        private void checkElementIndex(int index) {
            if (!(index > 0 && index < size)) {
               throw new IndexOutOfBoundsException(); 
            }
        }
    
    
        @Override
        public Iterator<T> iterator() {
            return new Iterator<T>() {
                private Node<T> curr = head;
    
                @Override
                public boolean hasNext() {
                    return curr != null;
                }
    
                @Override
                public T next() {
                    T data = curr.data;
                    curr = curr.next;
                    return data;
                }
    
                @Override
                public void remove() {
    
                }
            };
        }
    }
    
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  • 原文地址:https://www.cnblogs.com/warrior/p/13280623.html
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