摘要: https://ac.nowcoder.com/acm/contest/11171/E 给定 \(N,k\),\(1\le N\le 5\cdot 10^6,-1\le k\le 10^9\),求: \[ \sum_{i=1}^N\sum_{j=1}^N\varphi(ij\gcd(i,j)^k) 阅读全文
posted @ 2022-04-13 19:50 zzt1208 阅读(79) 评论(1) 推荐(1) 编辑