数据结构学习之栈

数据结构（底层实现+Java版本）

• 栈（数组方式实现）

public interface Stack<E> {

    int getsize();

    boolean isEmpty();

    void push(E e);

    E pop();

    E peek();

}


public class ArrayStack<E> implements Stack<E> {

    //复用动态数组来实现栈结构
    Array<E> array;

    public ArrayStack(int capacity) {
        array = new Array<>(capacity);

    }

    public ArrayStack() {
        array = new Array<>();
    }


    @Override
    public int getsize() {
        return array.getSize();
    }

    @Override
    public boolean isEmpty() {
        return array.isEmpty();
    }

    public int getCapacity() {
        return array.getCapacity();
    }

    @Override
    public void push(E e) {
        array.addLast(e);
    }

    @Override
    public E pop() {
        return array.removeLast();
    }

    @Override
    public E peek() {
        return array.getLast();
    }

    @Override

    public String toString() {
        StringBuilder res = new StringBuilder();
        res.append("Stack:");
        res.append(" [");
        for (int i = 0; i < array.getSize(); i++) {
            res.append(array.get(i));
            if (i != array.getSize() - 1) {
                res.append(", ");
            }
        }

        res.append("] top");
        return res.toString();
    }
}

• 栈（链表方式实现）

public class LinkedListStack<E> implements Stack<E> {

    private LinkedList<E> list;

    public LinkedListStack() {
        list = new LinkedList<>();
    }

    @Override
    public int getsize() {
        return list.getSize();
    }

    @Override
    public boolean isEmpty() {
        return list.isEmpty();
    }

    @Override
    public void push(E e) {
        list.addFirst(e);

    }

    @Override
    public E pop() {
        return list.removeFirst();
    }

    @Override
    public E peek() {
        return list.getFirst();
    }

    @Override
    public String toString(){
        StringBuilder res = new StringBuilder();
        res.append("Stack: top");
        res.append(list);

        return res.toString();
    }
}