Java 两个栈实现队列和两个队列实现栈-蒲公英云

Java 两个栈实现队列和两个队列实现栈

以你之姓@ 2022-07-18 01:24 370阅读 0赞

两个队列实现栈：

package test;
import java.util.Stack;
public class TwoStackQueue {
    public Stack<Integer> stackPush;
    public Stack<Integer> stackPop;
    public TwoStackQueue(){
        stackPush = new Stack<Integer>();
        stackPop = new Stack<Integer>();
    }
    public void push(int num){
        while(!stackPop.isEmpty()){
            stackPush.push(stackPop.pop());
        }
        stackPush.push(num);
    }
    public int pop(){
        while(!stackPush.isEmpty()){
            stackPop.add(stackPush.pop());
        }
        return stackPop.pop();
    }
    public static void main(String args[]){
        TwoStackQueue test = new TwoStackQueue();
        test.push(1);
        test.push(2);
        test.push(3);
        System.out.println(test.pop());
     }
}

两个队列实现栈

package test;
import java.util.LinkedList;
import java.util.Queue;
public class TwoQueueStack {
    public static Queue<Integer> queue1;
    public static Queue<Integer> queue2;
    public TwoQueueStack(){
        queue1 = new LinkedList<Integer>();
        queue2 = new LinkedList<Integer>();
    }
    public void push(int x) {
        if(empty()){
            queue1.offer(x);
        }else{
            if(!queue1.isEmpty()){
                queue2.offer(x);
                while(!queue1.isEmpty()){
                    queue2.offer(queue1.poll());
                }
            }else if(!queue2.isEmpty()){
                queue1.offer(x);
                while(!queue2.isEmpty()){
                    queue1.offer(queue2.poll());
                }
            }
        }
    }
    public static int pop(){
        if(!queue1.isEmpty()){
            return queue1.poll();
        }else if(!queue2.isEmpty()){
            return queue2.poll();
        }else{
            return 0;
        }
    }
    public boolean empty() {
        return queue1.isEmpty() & queue2.isEmpty();
    }
    public static void main(String args[]){
        TwoQueueStack test = new TwoQueueStack();
        test.push(1);
        test.push(2);
        System.out.println(pop());
    }
}