题意 ural 做法 求出一个原根\(\omega\),对于每个数\(x\)写成\(x=\omega^{k}\)的形式,\(\delta(x)=\frac{p-1}{k}\) 我们不关心群具体的东西,用\(\omega\)表示,求阶就方便了 但在模意义下,区间乘求\(gcd\),是件很困难的事 但商分一下,\(b_i=a_{i}\times a_{i-1}^{-1}\),就可以单点修改了 题外话 题目链接网址含有敏感词...只能放个百度的链接了…

Sol 线段树+Hash. 首先暴力 等差子序列至少3项就可以了,就枚举中项,枚举公差就可以了,只需要一个数在中项前出现,另一个数在中项前没出现过就可以了.复杂度 \(O(n^2)\) 然后我想了一个虽然复杂度没变(因为我不会设计这个数据结构...) 但是好像有点用的算法,就是枚举中项,考虑从一个中项转移到另一个中项,那就是 \(\pm \Delta\) 就可以了...如果能够用数据结构维护这个操作,那就灰常好了.变换中项也就是变换折叠的位置吧. 标算呢...就是用线段树维护Hash,一个数字出…

题目链接 题意:求给定的字符串的最长回文子串 分析:做法是构造一个新的字符串是原字符串+反转后的原字符串(这样方便求两边回文的后缀的最长前缀),即newS = S + '$' + revS,枚举回文串中心位置,RMQ询问LCP = min (height[rank[l]+1] to height[rank[r]]),注意的是RMQ传入参数最好是后缀的位置,因为它们在树上的顺序未知,且左边还要+1. #include <cstdio> #include <algorithm> #in…

2071. Juice Cocktails Time limit: 1.0 secondMemory limit: 64 MB Once n Denchiks come to the bar and each orders a juice cocktail. It could be from 1 to 3 different juices in each cocktail. There are three juices in the bar: apple, banana and pineappl…

2073. Log Files Time limit: 1.0 secondMemory limit: 64 MB Nikolay has decided to become the best programmer in the world! Now he regularly takes part in various programming contests, attentively listens to problems analysis and upsolves problems. But…

2070. Interesting Numbers Time limit: 2.0 secondMemory limit: 64 MB Nikolay and Asya investigate integers together in their spare time. Nikolay thinks an integer is interesting if it is a prime number. However, Asya thinks an integer is interesting i…

2069. Hard Rock Time limit: 1.0 secondMemory limit: 64 MB Ilya is a frontman of the most famous rock band on Earth. Band decided to make the most awesome music video ever for their new single. In that music video Ilya will go through Manhattan standi…

2068. Game of Nuts Time limit: 1.0 secondMemory limit: 64 MB The war for Westeros is still in process, manpower and supplies are coming to an end and the winter is as near as never before. The game of thrones is unpredictable so Daenerys and Stannis…

2067. Friends and Berries Time limit: 2.0 secondMemory limit: 64 MB There is a group of n children. According to a proverb, every man to his own taste. So the children value strawberries and raspberries differently. Let’s say that i-th child rates hi…

2066. Simple Expression Time limit: 1.0 secondMemory limit: 64 MB You probably know that Alex is a very serious mathematician and he likes to solve serious problems. This is another problem from Alex. You are given three nonnegative integers a, b, c.…