Java 两个栈实现队列和两个队列实现栈

以你之姓@ 2022-07-18 01:24 256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());
        }
    }