[第二轮] 3/4-3/10 CareerCup 3.5

Implement a MyQueue class which implements a queue using two stacks.

发帖规范:
http://www.1point3acres.com/bbs/thread-48094-1-1.html
http://www.1point3acres.com/bbs/thread-32423-1-1.html

In short, use the pop of the second stack to simulate queue.pop() and the push of the first stack to simulate the queue.push(). Values should be copied between two stacks....my poor english....

Your English is fineI know what you mean

IDEA: whenever a PUSH operation is needed, just push the element into STACK1; if FRONT operation is needed, then check if STACK2 is empty or not: if YES, then put all elements in STACK1 to STACK2; if NO, just give the TOP of STACK2.

c++ implementation

https://github.com/StanleyLee/CareerCup/blob/master/3_5.cpp

贴个java,请大神指点。

public class MyQueue {

        private Stack<Integer> s1, s2;

        public void enqueue(int x) {
                s1.push(x);
        }

        public int dequeue() {

                if (s2.isEmpty()) {

                        while (!s1.isEmpty()) {
                                s2.push(s1.pop());
                        }
                }

                return s2.pop();
        }

}

keller2046 发表于 2013-3-6 13:33
贴个java,请大神指点。

public class MyQueue {

重新读发帖要求，发现还没有github账号，面壁。。。

enqueue：对st1压栈
dequeue：如果st2不是空，pop st2。如果st2是空，把st1所有元素pop并push进st2，然后pop st2.

https://gist.github.com/skxie/780678436c5b8d3bdb9f

两个stack，第一个吃，第二个吃 第一个吐出来的，然后再吐
https://gist.github.com/lazyGoose/5108785

https://github.com/moophis/careercup/blob/master/3.5.cpp

The method is similar with others.

https://gist.github.com/ThunderXu/5124091
same with others

And I think may make a func that runs periodically which pops elements of stack1 to stack2 if stack2 is empty instead of doing this when dequeue.