剑指OFFER----面试题09. 用两个栈实现队列

链接：https://leetcode-cn.com/problems/yong-liang-ge-zhan-shi-xian-dui-lie-lcof/

代码：

class CQueue {
public:
    stack<int> stack_a;
    stack<int> stack_b;
    CQueue() {

    }

    void appendTail(int value) {
        stack_a.push(value);
    }

    int deleteHead() {
        if (stack_a.empty() && stack_b.empty())
            return -1;
        else if (stack_b.empty() && !stack_a.empty())
        {
            while (!stack_a.empty())
            {
                stack_b.push(stack_a.top());
                stack_a.pop();
            }
        }
        int temp = stack_b.top();
        stack_b.pop();
        return temp;     
    }
};