用两个栈实现队列

import java.util.Stack;

public class  {
    Stack<Integer> stackPush = new Stack<Integer>();
    Stack<Integer> stackPop = new Stack<Integer>();
    
    public void push(int node) {
        stackPush.push(node);
    }
    
    public int pop() {
        if (stackPop.isEmpty()){
            while(!stackPush.isEmpty()){
                stackPop.push(stackPush.pop());
            }
        }
        return stackPop.pop();
    }
}