使用两个栈实现一个队列
template<class T>
struct MyQueue
{
void push(T &t)
{
s1.push(t);
}
T front()
{
if(s2.empty())
{
if(s1.size() == 0) throw;
while(!s1.empty())
{
s2.push(s1.top());
s1.pop();
}
}
return s2.top();
}
void pop()
{
if(s2.empty())
{
while(!s1.empty())
{
s2.push(s1.top());
s1.pop();
}
}
if(!s2.empty())
s2.pop();
}
stack<T> s1; //入栈
stack<T> s2; //出栈
};