geometry for idiots

The method of drawing function images by using the stroke method is not limited to a function, but is suitable for drawing any image of a function. The following is an example of function y=x3, which describes how to draw a function image using the geometry artboard to draw points.　　The following steps are described:1. Execute the draw-Define coordinate system command, create a new coordinate system, and set the label of the origin coordinates to O.2.

Note: This is one of the brief personal summary series of the MOOC course in Deng Junhui, Tsinghua University, in spring 2016, and I will synchronize the course content updates. However, it is possible to write not exactly the course content, but also some personal understanding. If you are interested in computational geometry after reading this article, please go to the appropriate MOOC platform to learn the full course of teacher Deng. Such well-des

Test instructions is a world with many countries, each with n buildings, including a power station and N-1 buildings, all of which are surrounded by a convex hull that is the size of the country. A missile that explodes within a country can cause the country to power down.Step 1: Find the convex hull of each country (I use the horizontal sort is all kinds of pits, change the fork by the sort before, mainly is the back area of the time need this fork to sort information).Step 2: Determine whether

numbers x1, y1, x2, y2, where (x1, y1), (x2, y2) is t He coordinates of the trees of the opposite neighbors. Input is terminated by end of file.OutputFor each line of input produce one line of output which contains the line "impossible." without the quotes, if yo U cannot determine the coordinates of the other and the trees. Otherwise, print four floating point numbers separated by a single space with ten digits after the decimal point ax1, Ay1, Ax2, Ay2, where (Ax1, Ay1) and (AX2, Ay2) is the

The main topic: given some alloys, choose the least alloy, so that these alloys can be synthesized according to the required alloyFirst of all, the idea of this problem is very strange to see how this problem can be thought of computational geometry and calculate geometry and how to hang with Floyd good strongFirst because a+b+c=1 so we just have to get a and B can c=1-a-b so C can not read into theAnd then

) {if(X[i]==x[j] and y[i]==Y[j]) {Same++; Continue; } fraction k; K.son= ABS (Y[j]-y[i]);//No, no--K.mom = ABS (x[j]-X[i]); Scopes[len++] =K; } //sort O (NLGN)Qsort (Scopes,len,sizeof(fraction), cmp_fraction); //calculation frequency up to O (n) intMaxFreq =1; intFreq =1; for(intj =1; J j) {if(scopes[j]==scopes[j-1]) Freq++; Else{//it's broken. if(freq>maxFreq) MaxFreq=freq; Freq=1; } } if(freq>maxFreq) MaxFreq=freq; Freqs[freqs_len+ +] = Ma

vector OPI and OPJ is greater than 0, then the vector opj is in the counterclockwise direction of the vector OPI, that is, the point PJ is less than the dot pi.According to Method 2, the code for sorting the polygon point set is as follows: 1 typedef struct POINT 2 {3 int x; 4 int y; 5}point; 6//If point A is greater than point B, that is, point A is clockwise in point B, returns True, otherwise false 7 bool pointcmp (const point a,const-b,const point center) 8 {9 if (a.x >= 0 b.x Resources:h

the subsequent point is guaranteed to be greater than the to time of the current time.PS: If the direct input according to double type will be reported time-out ....Code:#include #include#include#include#include#include#includeSet>#include#include#includestring>using namespaceStd;inlineDoublePow2 (Doublex) { returnx*x;}structnode{Double from, to;} t[100005];BOOLCMP (Node A, Node B) {if(A.to! =b.to)returnA.to b.to; Else returnA. from from;}intN, R, CNT, ans;intpx, py, PZ;voidWork () {

the cross product: 1: The result is that A and B form the parallelogram area of the adjacent edge. 2: The result has a positive negative, there is a sin (a, b) and its angle, the angle is greater than 180 ° is negative. 3: Cross product does not meet the Exchange lawApplication: (1: Through the results of positive and negative judgment between the two vectors of the cis-counterclockwise relationship if a X B > 0 means a in the clockwise direction of b if a x B (2: Judge the zigzag turn, can be