摘要："传送门" 题意： 给两个整数a,m $( 1 \le a include include include include include include include include using namespace std; typedef long long ll; const int max 阅读全文

摘要：题意： 给你一个区间[L,R]，求L到R的所有数的因子的k次幂之和 思路： 对于（1—r）每个数，求它的因子和。如何求呢？我们可以枚举（i=1-r），以i作为因子的iki^k，然后对于每个有以i为因子的数都加上它,对于每个数的因子次幂和放到a[i]数组里。例如以2为因子的有2,4,6,8,10…,然 阅读全文

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