用队列实现栈

 

 

 

 1 import java.util.ArrayDeque;
 2 import java.util.Queue;
 3 
 4 public class StackByQueue {
 5     private Queue<Integer> inQueue;
 6     private Queue<Integer> outQueue;
 7     private Queue<Integer> tempQueue = null;
 8 
 9     /**
10      * Initialize your data structure here.
11      */
12     public StackByQueue() {
13         this.inQueue = new ArrayDeque<>();
14         this.outQueue = new ArrayDeque<>();
15     }
16 
17 
18     /**
19      * Push element x onto stack.
20      */
21     public void push(int x) {
22         inQueue.offer(x);
23         while (!outQueue.isEmpty()) {
24             inQueue.offer(outQueue.poll());
25         }
26         tempQueue = inQueue;
27         inQueue = outQueue;
28         outQueue = tempQueue;
29 
30     }
31 
32     /**
33      * Removes the element on top of the stack and returns that element.
34      */
35     public int pop() {
36         return outQueue.poll();
37     }
38 
39     /**
40      * Get the top element.
41      */
42     public int top() {
43         return outQueue.peek();
44     }
45 
46     /**
47      * Returns whether the stack is empty.
48      */
49     public boolean empty() {
50         return outQueue.isEmpty();
51     }
52 
53 
54     public static void main(String[] args) {
55         StackByQueue obj = new StackByQueue();
56         obj.push(1);
57         obj.push(2);
58 
59         int param_2 = obj.pop();
60         int param_3 = obj.top();
61         boolean param_4 = obj.empty();
62     }
63 
64 }

 

posted @ 2020-03-25 18:43  iiiorz  阅读(222)  评论(0)    收藏  举报