1）队列的基本实现
/**
* 队列实现
*/
Queue<Integer>queue=new LinkedList<>();
//添加元素
queue.offer(1);
queue.offer(2);
queue.offer(3);
//第二种方式添加
/*queue.add(1);
queue.add(2);
queue.add(3);*/
//取出元素
Integer poll1 = queue.poll();
System.out.println(poll1);
//查找元素
Integer peek = queue.peek();
System.out.println("查找并不实际弹出队列："+peek);
2）栈的基本实现
/**
* 栈实现1
*/
Deque<Integer>stack=new LinkedList<>();
stack.push(1);
stack.push(2);
stack.push(3);
Integer pop = stack.pop();
System.out.println("弹出栈："+pop);
Integer peek2 = stack.peek();
System.out.println("不实际弹出栈，查询："+peek2);
/**
* 栈实现2
*/
Stack<Integer> stack1=new Stack<>();
stack1.push(1);
stack1.push(2);
stack1.push(3);
Integer pop1 = stack1.pop();
System.out.println("弹出栈："+pop1);
Integer peek3 = stack1.peek();
System.out.println("不实际弹出栈，查询："+peek3);
3）解题：队列实现栈（对应力扣225题）
public class MyStack {
Queue<Integer>queue1=null;
Queue<Integer>queue2=null;
public MyStack() {
queue1=new LinkedList<Integer>();
queue2=new LinkedList<Integer>();
}
public void push(int x) {
queue2.add(x);
while (!queue1.isEmpty()){
queue2.add(queue1.poll());
}
Queue<Integer> tempQueue=queue1;
queue1=queue2;
queue2=tempQueue;
}
public int pop() {
return queue1.poll();
}
public int top() {
return queue1.peek();
}
public boolean empty() {
return queue1.isEmpty();
}
}
4）解题：栈实现队列（对应力扣232题）
//栈实现队列
public class MyQueue {
Stack<Integer>stack1=null;
Stack<Integer>stack2=null;
public MyQueue() {
stack1=new Stack<>();
stack2=new Stack<>();
}
public void push(int x) {
stack1.push(x);
}
public int pop() {
if (stack2.isEmpty()){
while (!stack1.isEmpty()){
stack2.push(stack1.pop());
}
}
return stack2.pop();
}
public int peek() {
int result =pop();
stack2.push(result);
return result;
}
public boolean empty() {
return stack1.isEmpty() && stack2.isEmpty();
}
}
