题解 | 用两个栈实现队列

#include <exception>
class Solution
{
public:
    void push(int node) {
        stack1.push(node);
    }

    int pop() {
        if (stack2.size()<=0){
            while (stack1.size()>0) {
                int data = stack1.top();
                stack1.pop();
                stack2.push(data);
            }
        }

        if(stack2.size() == 0) {
            return -1;
        }

        int head = stack2.top();
        stack2.pop();

        return head;
    }

private:
    stack<int> stack1;
    stack<int> stack2;
};

将两个stack作为入栈和出栈；