KirinSB

摘要： 思路：虽然看到题目就想到了用欧拉函数做，但就是不知道怎么做...当a b互质时GCD（a,b）= 1，由此我们可以推出GCD（k*a,k*b）= k。设ans[i]是1~i-1与i的GCD之和，所以最终答案是将ans[0]一直加到ans[n]。当 k*i==j 时，a... 阅读全文

摘要： You task is to find minimal natural number N, so that N! contains exactly Q zeroes on the trail in decimal notation. As you know N! = ... 阅读全文

摘要： Given two integers, a and b, you should check whether a is divisible by b or not. We know that an integer a is divisible by an integer... 阅读全文

摘要： Harmonic NumberIn mathematics, the nth harmonic number is the sum of the reciprocals of the first n natural numbers:In this problem, y... 阅读全文

摘要： Pairs Forming LCMFind the result of the following code:long long pairsFormLCM( int n ) { long long res = 0; for( int i = 1; i #i... 阅读全文

摘要： Goldbach`s Conjecture Goldbach's conjecture is one of the oldest unsolved problems in number theory and in all of mathematics. It stat... 阅读全文

摘要： Leading and Trailing You are given two integers: n and k, your task is to find the most significant three digits, and least significan... 阅读全文

摘要： 题意：一个有向图。第一问：最少给几个点信息能让所有点都收到信息。第二问：最少加几个边能实现在任意点放信息就能传遍所有点思路：把所有强连通分量缩成一点，然后判断各个点的入度和出度tarjan算法：问问神奇海螺啥是tarjan代码：#include#include#inc... 阅读全文

摘要： 题意：给一个矩形（非正方形）面积a和最小边长b，要求边长均大于b，求这样的矩形有几个思路：先用到了之前学的质因数分解，还有一个新的公式：然后我们可以先算出a的所有约数，因为只算约数个数面积重复，所以要/2；然后暴力出#include#include#include#i... 阅读全文

摘要： Bi-shoe and Phi-shoeBamboo Pole-vault is a massively popular sport in Xzhiland. And Master Phi-shoe is a very popular coach for his su... 阅读全文