题目大意:给定 N(1<N<=5000) 个不同元素组成的集合,求从中选出若干数字组成的等差数列最长是多少. 题解:直接暴力有 \(O(n^3)\) 的算法,即:枚举等差数列的前两个值,再暴力枚举后面的值进行匹配即可,不过这样做直接去世.. 考虑 \(dp[i][j]\) 表示以第 i 个数为数列倒数第二位,第 j 个数为等差数列中的最后一位的最长序列的长度,则:\(dp[i][j]=max\{dp[l][i]+1,a[i]-a[l]=a[j]-a[i]\&\&0<l&l…

传送门:https://codeforces.com/gym/102082/attachments 题解: 代码: /** * ┏┓ ┏┓ * ┏┛┗━━━━━━━┛┗━━━┓ * ┃ ┃ * ┃ ━ ┃ * ┃ > < ┃ * ┃ ┃ * ┃... ⌒ ... ┃ * ┃ ┃ * ┗━┓ ┏━┛ * ┃ ┃ Code is far away from bug with the animal protecting * ┃ ┃ 神兽保佑,代码无bug * ┃ ┃ * ┃ ┃ * ┃ ┃ * ┃…

链接 G题 https://codeforces.com/gym/102082 使其成为单峰序列需要交换多少次相邻的数. 树状数组维护逆序对. 对于每个序列中的数,要么在单峰的左侧,要么在单峰的右侧,所以从左边开始维护每个数相对于左侧的逆序对数量,从右边开始维护每个数相对于右侧的逆序对数量.取小加入答案即可. #include <bits/stdc++.h> #define debug(x) cout << #x << ": " << x…

ACM-ICPC Asia Beijing Regional Contest 2018 Reproduction hihocoder1870~1879 A 签到,dfs 或者 floyd 都行. #include<bits/stdc++.h> using namespace std; typedef long long LL; typedef long double LD; typedef pair<int,int> pii; typedef pair<LL,int>…

P2 : Heshen's Account Book Time Limit:1000ms Case Time Limit:1000ms Memory Limit:512MB Description Heshen was an official of the Qing dynasty. He made a fortune which could be comparable to a whole country's wealth by corruption. So he was known as t…

P1 : Jin Yong’s Wukong Ranking List Time Limit:1000ms Case Time Limit:1000ms Memory Limit:512MB Description Jin Yong was the most famous and popular Chinese wuxia (The one who fight bad people by his Wukong i.e. Wushu and Kongfu) novelist who lived i…

摘要 本文主要给出了2018 ACM-ICPC Asia Beijing Regional Contest的部分题解,意即熟悉区域赛题型,保持比赛感觉. Jin Yong’s Wukong Ranking List 题意 输入关系组数n和n组关系,每组关系是s1 > s2,问第一出现矛盾的组,或者没有矛盾就输出0. 解题思路 第一感觉是拓扑排序,未完,又写了一个深搜的传递闭包,1 A,和2018年河南省赛的题很像. 代码 #include <cstdio> #include <ma…

摘要: 本文是The 2018 ACM-ICPC Asia Qingdao Regional Contest(青岛现场赛)的部分解题报告,给出了出题率较高的几道题的题解,希望熟悉区域赛的题型,进而对其他区域赛的准备有借鉴意义. Function and Function 题意 给出x和k,计算gk(x). 解题思路 通过观察发现,g函数经过一定次数的递推一定会在0和1之间变换,所以循环内加判断提前结束递推即可. 易错分析 注意计算f(0)返回的是1的问题,下面的写法避免了这种错误. 代码实现 #…

The 2018 ACM-ICPC Asia Qingdao Regional Contest 青岛总体来说只会3题 C #include<bits/stdc++.h> using namespace std; #define maxn 3000005 char a[maxn],b[maxn]; int c[maxn],ll[maxn],rr[maxn]; int main(){ int t; cin>>t; while(t--){ int n; scanf("%d&qu…

Conquer a New Region Time Limit: 5 Seconds      Memory Limit: 32768 KB The wheel of the history rolling forward, our king conquered a new region in a distant continent. There are N towns (numbered from 1 to N) in this region connected by several road…