You're given a matrix A of size n × n. Let's call the matrix with nonnegative elements magic if it is symmetric (so aij = aji), aii = 0 and aij ≤ max(aik, ajk) for all triples i, j, k. Note that i, j, k do not need to be distinct. Determine if the ma…
ZOJ 2477 Magic Cube(魔方) Time Limit: 2 Seconds Memory Limit: 65536 KB This is a very popular game for children. In this game, there's a cube, which consists of 3 * 3 * 3 small cubes. We can unwrap the cube, it will become like this: 这是个有名的儿童游戏.游戏…
[CF1097F]Alex and a TV Show(bitset) 题面 洛谷 CF 题解 首先模\(2\)意义下用\(bitset\)很明显了. 那么问题在于怎么处理那个\(gcd\)操作. 然后就莫比乌斯反演一下:\(f[n]=\sum\limits_{n|d}g[d],g[n]=\sum\limits_{n|d}\mu(\frac{d}{n})f[d]\),发现这样子搞完之后,如果要处理集合\(g\)的\(gcd\)操作,就是把\(g\)变成\(f\)之后再按位乘起来(二进制意义下的按…
题目描述: C. Producing Snow time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Alice likes snow a lot! Unfortunately, this year's winter is already over, and she can't expect to have any more of i…