Leetcode232.栈实现队列

此题与剑指offer第九题类似,都是用两个维护栈实现的队列操作

栈stack1维护队列的offer操作

栈stack2维护队列的poll操作

class MyQueue {
    linkedList stack1=new linkedList();
    linkedList stack2=new linkedList();
    public MyQueue() {

    }

    public void push(int x) {
        stack1.push(x);
    }

    public int pop() {
        if(stack1.isEmpty()&&stack2.isEmpty()){
            return -1;
        }
        if(stack2.isEmpty()){
            while(!stack1.isEmpty()){
                stack2.push(stack1.pop());
            }
        }
        return stack2.pop();
    }

    public int peek() {
        int pee=pop();
        stack2.push(pee);
        return pee;
    }

    public boolean empty() {
        if(stack2.isEmpty()&&stack1.isEmpty()){
            return true;
        }
        return false;
    }
}