队列：火车过隧道。。。火车头先进隧道先出隧道、、、先进先出

　　栈：桶里倒水再倒出。。。先进后出。。。

两个堆栈实现队列与两个队列实现堆栈

package Test2016.test;import java.util.LinkedList;import java.util.Queue;import java.util.Stack;public class Test20160329 {    public static void main(String[] args) {            /**         * @desc 两个堆栈实现队列         * @idea 堆栈:先进后出,队列:先进先出         * */        MyQueue myQueue = new MyQueue();                System.out.println("入队列顺序:");        for (int i = 1; i <= 10; i++) {            System.out.print(i + " ");            myQueue.push_q(i);        }                System.out.println("\n用堆栈实现【队列】弹出:");        for (int i = 0; i < 10; i++) {            System.out.print(myQueue.pop_q() + " ");        }                System.out.println("\n######################");                /**         * @desc 两个队列实现堆栈         * @idea 堆栈:先进后出,队列:先进先出         * */        MyStack myStack = new MyStack();                System.out.println("入堆栈顺序:");        for (int i = 1; i <= 10; i++) {            System.out.print(i + " ");            myStack.push_s(i);        }                System.out.println("\n用队列实现【堆栈】弹出:");        for (int i = 0; i < 10; i++) {            System.out.print(myStack.pop_s() + " ");        }            }}class MyQueue {        private Stack
     
       s1 = null;    private Stack
      
        s2 = null;        public MyQueue() {        s1 = new Stack
       
        ();        s2 = new Stack
        
         ();    }        public Integer push_q(Integer p) {        s1.push(p);        return p;    }        public Integer pop_q() {        Integer res = null;                if (!s2.isEmpty()) {            res = s2.pop();        } else {            while (!s1.isEmpty()) {                res = s1.pop();                s2.push(res);            }                        if (!s2.isEmpty()) {                res = s2.pop();            }        }        return res;    }}class MyStack {        private Queue
         
           q1 = null;    private Queue
          
            q2 = null; public MyStack() { q1 = new LinkedList
           
            (); q2 = new LinkedList
            
             (); } public Integer push_s(Integer p) { q1.add(p); return p; } public Integer pop_s() { Integer res = null; boolean flag = true; //标识变量 if (q2.size() > 0 && flag == true) { flag = false; while (q2.size() > 0) { if (q2.size() > 0) { res = q2.remove(); q1.add(res); } } q1.remove(res); } else if (q1.size() > 0 && flag == true) { while (q1.size() > 0) { if (q1.size() > 0) { res = q1.remove(); q2.add(res); } } q2.remove(res); } return res; }}
            
           
          
         
        
       
      
     

程序运行输出:

入队列顺序:1 2 3 4 5 6 7 8 9 10 用堆栈实现【队列】弹出:1 2 3 4 5 6 7 8 9 10 ######################入堆栈顺序:1 2 3 4 5 6 7 8 9 10 用队列实现【堆栈】弹出:10 9 8 7 6 5 4 3 2 1