刷题day1-2

用数组结构实现大小固定的队列和栈

实现队列 通过一个size成员变量来记录队列的大小，避免复杂的公式

public class MyQueue { private int[] nums; private int size = 0;//队列大小 private int head = 0;//队头 private int end = 0;//队尾 public MyQueue(int size) { nums = new int[size]; } /** * 入队操作 * @param num */ public void enQueue(int num) { if (size == nums.length) { throw new ArrayIndexOutOfBoundsException("the queue is full"); } nums[end] = num; end = ++end == nums.length ? 0 : end; size++; } /** * 出队操作 * @return */ public int deQueue() { if (size == 0) { throw new ArrayIndexOutOfBoundsException("the queue is empty"); } int tmp = nums[head]; head = ++head == nums.length ? 0 : head; size--; return tmp; } }

实现栈

public class MyStack { private int[] nums; private int size = 0;//栈的大小 private int top = -1;//栈顶位置 public MyStack(int size) { nums = new int[size]; } /** * 入栈操作 * @param num */ public void push(int num) { if (size == nums.length) { throw new ArrayIndexOutOfBoundsException("your stack is full"); } nums[++top] = num; size++; } /** * 出栈操作 * @return */ public int pop() { if (size == 0) { throw new ArrayIndexOutOfBoundsException("your stack is empty"); } int tmp = nums[top]; top--; size--; return tmp; } }