首先可以证明,点积最值的点对都是都是在凸包上,套用题解的证明:假设里两个点都不在凸包上, 考虑把一个点换成凸包上的点(不动的那个点), 不管你是要点积最大还是最小, 你都可以把那个不动的点跟原点拉一条直线, 然后把所有的点投影到这条直线上, 要找的无非就是这条直线最前面或者最后面的两个点.这两个点不可能是不在凸包上的点.同理我们可以把另一个点移到凸包上. 由于数据随机生成,那么生成凸包上的点的个数的期望是logn,而且删的点落在凸包上的概率是logn/n,所以只需要对每次删点和加点暴力重构凸包即…

Data Structure Problem Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://acm.uestc.edu.cn/#/problem/show/483 Description Data structure is a fundamental course of Computer Science, so that each contestant is highly likely to solve this data structu…

C - Data Structure? Time Limit:5000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Practice id=27724" class="ui-button ui-widget ui-state-default ui-corner-all ui-button-text-only" style="display:inline-…

Data Structure? Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Problem Description Data structure is one of the basic skills for Computer Science students, which is a particular way of storing and organizing data…

原题链接:http://acm.hdu.edu.cn/showproblem.php?pid=4217 可用线段树写,效率要高点. 这道题以前用c语言写的treap水过了.. 现在接触了c++重写一遍... 不带重复元素的插入删除第k大带垃圾回收,具体如下: #include<cstdio> #include<cstdlib> #include<iostream> #include<algorithm> typedef long long ll; ; str…

题目链接  ZOJ Monthly, March 2018 Problem F 题意很明确 这个模数很奇妙,在$[0, mod)$的所有数满足任意一个数立方$48$次对$mod$取模之后会回到本身. 所以开$48$棵线段树,和一个永久标记.当对某个区间操作时对这个区间加一层永久标记. 即当前我要查找的第$x$层,实际找的是第$up[i] + x$层. 时间复杂度$O(48nlogn)$ #include <bits/stdc++.h> using namespace std; #define…

不难发现,问题即求满足以下条件的$(i,j)$对数: 1.$1\le i<j\le n$且$a_{i}=a_{j}$ 2.$\min_{i\le k\le j}y_{k}\ge l$且$\max_{i\le k\le j}y_{k}\le r$ 先考虑条件1,枚举$1\le x\le n$,并对满足$a_{i}=x$的$i$个数$cnt$分类讨论: 1.若$cnt\le B$(其中$B$为常数),那么$a_{i}=a_{j}=x$的区间个数和(指对所有这样的$x$)不超过$nB$,暴力预处理出此…

(四边形不等式的套路题) 对于某一组$a_{i}$,显然可以区间dp,设$f_{l,r}$表示区间$[l,r]$​的答案,则转移即$$f_{l,r}=\begin{cases}0&(l=r)\\\sum_{i=l}^{r}\sum_{j=l}^{r}dist(a_{i},a_{j})+\min_{l\le i<r}(f_{l,i}+f_{i+1,r})&(l<r)\end{cases}$$为了方便,对于$l<r$定义$f_{l,r}$的最优决策为后者取到$\min$时的(…

Basic Data Structure Time Limit: 7000/3500 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 872    Accepted Submission(s): 236 Problem Description Mr. Frog learned a basic data structure recently, which is called stac…

Basic Data Structure Time Limit: 7000/3500 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Problem Description Mr. Frog learned a basic data structure recently, which is called stack.There are some basic operations of stack: ∙ PUSH x: p…