摘要：
原题链接 Problem Description The Euler function phi is an important kind of function in number theory, (n) represents the amount of the numbers which are 阅读全文
摘要：
原题链接 http://acm.hdu.edu.cn/showproblem.php?pid=3501 Given a positive integer N, your task is to calculate the sum of the positive integers less than N 阅读全文