包子不卖包子

Dima is a beginner programmer. During his working process, he regularly has to repeat the following operation again and again: to remove every second element from the array. One day he has been bored ...

Description 又到了acm实验室半年一次的集训了.ACMers,只觉得整个世界都是程序设计,头晕目眩.现在实验室有n个队员,围成一圈开早会,汇报学习进度，他们等间距的分布在圆桌上，圆桌的周长为1000.这时候大丁突然想起来需要有个人下楼开门.所以决定随机找一个人下去开门.然后他就一如既往的随机到了小胖学长,小胖说了一句"我笑了",就离开了.为了继续圆桌会议,大丁决定...

Pikachu had an array with him. He wrote down all the non-empty subsequences of the array on paper. Note that an array of size n has 2n - 1 non-empty subsequences in it. Pikachu being mischievous as he...