摘要：
You are given an array aa consisting of nn integers. Your task is to say the number of such positive integers xx such that xx divides each number from 阅读全文
摘要：
On Octorber 21st, HDU 50-year-celebration, 50-color balloons floating around the campus, it's so nice, isn't it? To celebrate this meaningful day, the 阅读全文