题解 | #用两个栈实现队列#

using System.Collections.Generic;
class Solution
{
    Stack<int> sta1 = new Stack<int>();
    Stack<int> sta2 = new Stack<int>();
    int num2 = 0;
    public void push(int node) 
    {
        sta1.Push(node);
    }
    public int pop() 
    {
        if(num2 == 0){
            for(int i = sta1.Count; i > 0; i--){
                sta2.Push(sta1.Pop());
                num2++;
            }
        }
        num2--;
        return sta2.Pop();
    }
}