题解 | #用两个栈实现队列#

import java.util.Stack;

public class Solution {
    //栈1表示从队尾取元素
    Stack<Integer> stack1 = new Stack<Integer>();
    //栈2为栈1的逆序也就是从出队
    Stack<Integer> stack2 = new Stack<Integer>();

    public void push(int node) {
        stack1.push(node);

    }

    public int pop() {
       while (!stack1.isEmpty()){
           stack2.push(stack1.pop());
       }
       int res = stack2.pop();
       while (!stack2.isEmpty()){
           stack1.push(stack2.pop());
       }
       return res;
    }
}