题解 | #用两个栈实现队列#

class Solution

{
public:
    void push(int node) {
        stack2.push(node);
    }

    int pop() {
        if(stack1.empty()){
            while(!stack2.empty()){
                int x = stack2.top();
                stack2.pop();
                stack1.push(x);
            }
        }
        int y = stack1.top();
        stack1.pop();
        return y;
    }

private:
    stack stack1;
    stack stack2;
};