摘要：
ou are in a maze; seeing n doors in front of you in beginning. You can choose any door you like. The probability for choosing a door is equal for all 阅读全文
摘要：
注意了，求期望很多时候都是倒推的，而这所谓的倒推主要是指与目标距离之间的“步长大小”，与目标相距为n即为所求，也就是dp【0】 阅读全文
摘要：
imi learned a new thing about integers, which is - any positive integer greater than 1 can be divided by its divisors. So, he is now playing with this 阅读全文
摘要：
Given a dice with n sides, you have to find the expected number of times you have to throw that dice to see all its faces at least once. Assume that t 阅读全文