题意: 1.区间求 a[l]×L+a[l+1]×(L−1)+⋯+a[r−1]×2+a[r](L is the length of [ l, r ] that equals to r - l + 1) 2.单点修改 解析: 只有这两个操作 并且区间求得值与前缀和极为相似 所以嘛 就要想到树状数组 树状数组能够维护前缀和 所以区间 [ l, r ] 就是r的前缀和减去l的前缀和 但每个a[i]的系数都不同 求前缀和无用..所以要想到化简一下  把每个a[i]的系数都化为一样的或者定量 由上面的式子化…

262144K   Ryuji is not a good student, and he doesn't want to study. But there are n books he should learn, each book has its knowledge a[i]a[i]. Unfortunately, the longer he learns, the fewer he gets. That means, if he reads books from ll to rr, he…

Ryuji is not a good student, and he doesn't want to study. But there are n books he should learn, each book has its knowledge a[i]a[i]. Unfortunately, the longer he learns, the fewer he gets. That means, if he reads books from ll to rr, he will get a…

H.Ryuji doesn't want to study 27.34% 1000ms 262144K   Ryuji is not a good student, and he doesn't want to study. But there are n books he should learn, each book has its knowledge a[i]a[i]. Unfortunately, the longer he learns, the fewer he gets. That…

ACM-ICPC 2018 徐州赛区网络预赛 A.Hard to prepare 枚举第一个选的,接下来的那个不能取前一个的取反 \(DP[i][0]\)表示选和第一个相同的 \(DP[i][1]\)表示选和第一个取反的 \(DP[i][2]\)表示选其他的 状态转移方程直接看代码好了 //#pragma GCC optimize("O3") //#pragma comment(linker, "/STACK:1024000000,1024000000") #inc…

传送门 题面: In a world where ordinary people cannot reach, a boy named "Koutarou" and a girl named "Sena" are playing a video game. The game system of this video game is quite unique: in the process of playing this game, you need to consta…

In a world where ordinary people cannot reach, a boy named "Koutarou" and a girl named "Sena" are playing a video game. The game system of this video game is quite unique: in the process of playing this game, you need to constantly fac…

262144K   Morgana is learning computer vision, and he likes cats, too. One day he wants to find the cat movement from a cat video. To do this, he extracts cat features in each frame. A cat feature is a two-dimension vector <x, y>. If xi​= xj​ and yi…

Mur loves hash algorithm, and he sometimes encrypt another one's name, and call him with that encrypted value. For instance, he calls Kimura KMR, and calls Suzuki YJSNPI. One day he read a book about SHA-256,which can transit a string into just 256 b…

链接 https://nanti.jisuanke.com/t/31456 参考题解  https://blog.csdn.net/ftx456789/article/details/82590044 #include <bits/stdc++.h> #define pb push_back #define mp make_pair #define fi first #define se second #define all(a) (a).begin(), (a).end() #define…