题解 | #用两个栈实现队列#

import java.util.Stack;

public class Solution {
    Stack<Integer> stack1 = new Stack<Integer>();
    Stack<Integer> stack2 = new Stack<Integer>();
    //stack1是push栈
    //stack2是pop栈
    private void pushToPop(){
        if(stack2.empty()){
            while(!stack1.empty()){
                stack2.push(stack1.pop());

            }

        }
    }

    public void push(int node) {
        stack1.push(node);
        pushToPop();
        
    }
    
    public int pop() {
	  //实际上要加上非空判断
        pushToPop();
        return stack2.pop();

    }
}