convex nails

#include using namespace Std;typedef const long Long LL;struct node{int x, y;int POS;}PLANE[200020],TUBAO[200020],STT;int top;int n;Long Long multi (node A,node b,node c){ll mianji=1ll* (a.x-c.x) * (B.Y-C.Y) -1ll* (A.Y-C.Y) * (b.x-c.x);//area Formula judging positive negative valuereturn Mianji;}BOOL CMP (node A,node b){if (A.X==B.XAMP;AMP;A.Y==B.Y)Return a.pos>b.pos;//repeating point, dictionary large row in front (here if the dictionary is small, WA, the reason is unknown)if (!multi (stt,b,a))

　　Convex hull algorithm comparison image good understanding code writing is also relatively short, so before the exam should be no problem. >_ POJ1113　　At first, I didn't understand why we had to use convex hull, and thought it would be better to stick to the castle.The shortest perimeter in the case of a requirement to include all points in the subject is suddenly found. Is this the nature of the

Convex triangles: A convex polygon of any n vertex can be decomposed into n-2 triangles. The geometrical knowledge indicates that the inner angle of the triangle is 180 degrees. All triangular inner angles and for (n-2) *180 degrees. You can see that this and always equal the inner angle of the polygon and. For a convex polygon, the inner angle is not greater

Jostree Reprint Please specify the source http://www.cnblogs.com/jostree/p/4397990.htmlIn machine learning, it is a common problem to find the extremum of convex function, such as gradient descent method, Newton method, and so on, today we introduce a three-way method to find the extremum problem of a convex function.For a convex function such as $f (x), x\in [le

Maximum Distance between convex polygon Given two Convex PolygonPAndQTo find the point (P,Q)(PBelongPAndQBelongQ) To maximize the distance between them. Intuitively, these points cannot belong to the interior of their respective polygon. This condition is actually very similar to the diameter problem: Two convex polygonPAndQThe maximum distance is determined

As the most common method of divide and conquer, the bipartite method is applicable to monotonic functions and is used to approximate the value of a certain point. However, when a function is a convex function, the bipartite method cannot be applied. In this case, the three-way method can be used to show its strength "~~ , Similar to the binary definition of left and right, mid = (left + right)/2, midmid = (Mid + right)/2; If mid is near the extreme

Convex Polygon optimal triangle division (16:38:40 )[Edit] [Delete] ReprintedBytes Tags:It Category: Algorithm Convex Polygon optimal triangle division Note: P = {v0, V1,... vn-1} represents a convex side with N side v0, V1, v1v2,..., vn-1vn. V0 = Vn 1.Structure of triangle partitioning and related issuesNumber of operators in a polygon You ca

Many people actually know that the secondary derivative of the function can be used to judge the concave and convex of the function, but many people forget how to prove it. Here I will prove it again. Proof: If f (x) is continuous in (A, B) and can be imported twice, if f'' (x)> 0, the function is concave. If f (x) is greater than 0, the function is convex. Preface: First, we will give several theorems and

Link: http://poj.org/problem? Id = 2079 triangle Time limit:3000 Ms Memory limit:30000 K Total submissions:8173 Accepted:2423 DescriptionGiven n distinct points on a plane, your task is to find the triangle that have the maximum area, whose vertices are from the given points. InputThe input consists of several test cases. the first line of each test case contains an integer N, indicating the number of points on the plane. each of the following n lines contai

glass is like the polygon in Figure 1, you have just two ways to put it on the table, since all the other ways are not stable. however, the glass like the polygon in Figure 2 has three ways to be appreciated. Pay attention to the cases in Figure 3. We consider that those glasses are not stable. Inputthe input file contains several test cases. the first line of the file contains an integer t representing the number of test cases. For each test case, the first line is an integer n

Link: http://acm.sgu.ru/problem.php? Contest = 0 problem = 253 http://acm.hust.edu.cn/vjudge/contest/view.action? Cid = 27464 # Problem/a253. Theodore roosevelttime limit per test: 0.5 sec. Memory limit per test: 65536 kbinput: Standard Output: Standard Danger! Sudden attack on Russia! These are Americans "again", but this time they are serious. giant aircraft-carrier "Theodore Roosevelt" is entering the Baltic Sea. at one o 'clock American aircraft launched from the carrier bombed Petrozavodsk

Original question connection: http://poj.org/problem? Id = 1113 Give N points. You can see a wall so that the distance between all points and the wall is no less than l. Length of the wall .. Idea: first obtain the convex hull of N points, and then build a wall based on the convex hull. One part of the wall is the convex hull length, and the other part is a circl

Title Address: http://acm.hdu.edu.cn/showproblem.php?pid=3685Idea: First, the polygon center of gravity, placed on the edge must be convex edge. Determine if the center of gravity falls between the edges (find the distance between the line and the point to the line).40 04 08 44 4Note that the center of gravity cannot be on the perpendicular of the convex edge end.#include Hdu 3685 Rotational Painting (Polyg

the estimates. Sample Input 9 100200 400300 400300 300400 300400 400500 400500 200350 200200 200 Sample Output 1628 HintThe result is rounded to the nearest integer. Code: This question is to find a convex hull based on the given points and calculate its perimeter, plus the four extra 1/4 circles, that is, the circumference of a circle. Gift Wrapping is to tie a rope to a point and wrap around the outermost point. The key step is 1. Determine a st

Http://poj.org/problem? Id = 1228 The question is to give you n points and ask if you can determine the unique convex hull; Because these vertices are all boundary points, you only need to determine whether each boundary has> = 3 vertices. If yes, no. Why? It is assumed that there are two points, that is, there are only two endpoints of a line segment, so there can be any point out of the line to form a new convex