题解 | #用两个栈实现队列#

两个栈倒腾一下
进队列时，栈2非空就把栈2的挪到栈1里，进栈1
出队列时，栈1非空就把栈1的挪到栈2里，出栈2

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.isEmpty()){
            stack1.push(stack2.pop());
        }
        stack1.push(node);
    }

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