baidu_35522092的博客

Consider a N*N*N lattice. One corner is at (0,0,0) and the opposite one is at (N,N,N). How many lattice points are visible from corner at (0,0,0) ? A point X is visible from point Y iff no other latti

As we know, any positive integer C ( C >= 2 ) can be written as the multiply of some prime numbers:    C = p1×p2× p3× ... × pk which p1, p2 ... pk are all prime numbers.For example, if C = 24, t

Alice is playing a game with Bob. Alice shows N integers a 1, a 2, …, a N, and M, K. She says each integers 1 ≤ ai ≤ M. And now Alice wants to ask for each d = 1 to M, how many different sequenc

（对于100%的数据，1≤N,K≤10^9，1≤L≤H≤10^9，H-L≤10^5）这个题要是数据范围出小一些解释个裸的莫比乌斯反演。问题就是数据范围太鬼畜，我们无法筛出这个范围的莫比乌斯函数前缀和。这时就要用到杜教筛，它是用来解决 n本鶸对此理解还不深，大家可以自行上网找相关博客。这一篇就很好author: skywalkert original articl