题解 | #用两个栈实现队列#

import java.util.*;
import java.util.Stack;

public class Solution {
    Stack<Integer> stack1 = new Stack<Integer>();
    Stack<Integer> stack2 = new Stack<Integer>();
    
    public void push(int node) {
        while(!stack2.empty()){
            stack1.push(stack2.pop());
        }

        stack1.push(node);
    }
    
    public int pop() {
        while(!stack1.empty()){
            Integer i = stack1.pop();
            stack2.push(i);
        }

        return stack2.pop();
    }
}