两个栈实现队列

class Solution
{
public:
void push(int node)
{
stack1.push(node);
}

int pop()
{
  if(stack2.size()<=0)
  {
      while(!stack1.empty())
      {
          int data = stack1.top();
          stack2.push(data);
          stack1.pop();
      }
  }
    int head = stack2.top();
    stack2.pop();
    return head;
}

private:
stack stack1;
stack stack2;
};