Method push

S-Stack/StacksUsingQueue.cpp:24–36

push expensive

	}
    //push expensive
    void push(int x){
        q2.push(x);
        N++;

        while(!q1.empty()){
            q2.push(q1.front());
            q1.pop();
        }

        queue<int> temp = q1;
        q1 = q2;
        q2 = temp;
    }

    //pop easy
    void pop(){