java实现栈（数组和链表两种实现方式）

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栈的实现

栈是一种先进后出的数据结构,

首先用数组实现，底层使用数组：

public class MyArrayStack<T> {private Object[] objs = new Object[16];private int size = 0;public boolean isEmpty() {return size == 0;}public void clear() {// 将数组中的数据置为null, 方便GC进行回收for (int i = 0; i < size; i++) {objs[size] = null;}size = 0;}public int length() {return size;}public boolean push(T data) {// 判断是否需要进行数组扩容if (size >= objs.length) {resize();}objs[size++] = data;return true;}/** * 数组扩容 */private void resize() {Object[] temp = new Object[objs.length * 3 / 2 + 1];for (int i = 0; i < size; i++) {temp[i] = objs[i];objs[i] = null;}objs = temp;}public T pop() {if (size == 0) {return null;}return (T) objs[--size];}public String toString() {StringBuilder sb = new StringBuilder();sb.append("MyArrayStack: [");for (int i = 0; i < size; i++) {sb.append(objs[i].toString());if (i != size - 1) {sb.append(", ");}}sb.append("]");return sb.toString();}}

栈的链表实现，底层使用链表：

public class MyLinkedStack<T> {/** * 栈顶指针 */private Node top;/** * 栈的长度 */private int size;public MyLinkedStack() {top = null;size = 0;}public boolean isEmpty() {return size == 0;}public void clear() {top = null;size = 0;}public int length() {return size;}public boolean push(T data) {Node node = new Node();node.data = data;node.pre = top;// 改变栈顶指针top = node;size++;return true;}public T pop() {if (top != null) {Node node = top;// 改变栈顶指针top = top.pre;size--;return node.data;}return null;}/** * 将数据封装成结点 */private final class Node {private Node pre;private T data;}}

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