数据结构篇——栈和队列

面试题9：用两个栈实现队列 原题链接

class CQueue {
    stack<int> sk1, sk2;
public:
    CQueue() {
    }
    
    void appendTail(int value) {
        sk1.push(value);
    }
    
    int deleteHead() {
        if(sk2.empty()){
            if(sk1.empty())
                return -1;
            while(!sk1.empty()){
                sk2.push(sk1.top());
                sk1.pop();
            }    
        }
        int val = sk2.top();
        sk2.pop();
        return val;
    }
};

/**
 * Your CQueue object will be instantiated and called as such:
 * CQueue* obj = new CQueue();
 * obj->appendTail(value);
 * int param_2 = obj->deleteHead();
 */