描述

用栈实现队列232

分析

实现

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import java.util.Scanner;
import java.util.Stack;
 
//用栈实现队列232
public class ImplementQueueUsingStacks232 {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);

		MyQueue obj = new MyQueue();
		System.out.print("请输入入队数字：");
		int x = input.nextInt(); 
		obj.push(x);
		obj.push(66);
		int param_2 = obj.pop();
		System.out.println("\npop为： " + param_2);
		int param_3 = obj.peek();
		System.out.println("peek为： " + param_3);
		boolean param_4 = obj.empty();
		System.out.println("链表是否为空：" + param_4);
	}
}

//队列
class MyQueue {
	Stack<Integer> stackIn;
	Stack<Integer> stackOut;

    public MyQueue() {
    	stackIn = new Stack<>();
    	stackOut = new Stack<>();
    }
    
    public void push(int x) {
    	stackIn.push(x);
    }
    
    public int pop() {
    	in2Out();
    	return stackOut.pop();
    }
    
    public int peek() {
    	in2Out();
    	return stackOut.peek();
    }
    
    public boolean empty() {
    	return stackOut.isEmpty() && stackIn.isEmpty();
    }

    public void in2Out(){
    	if (!stackOut.isEmpty()) {
    		return;
    	}
    	while(!stackIn.isEmpty()){
    		stackOut.push(stackIn.pop());
    	}
    }
}

总结