UVA 11800 determine the Shape

Vjudge on the topic Link: Determine the Shape

The second way alone a out of the computational geometry water problem, test instructions is to give you four points, let you judge what kind of quadrilateral it is: square, rectangle, diamond, parallelogram, trapezoidal or ordinary quadrilateral.

According to the characteristics of each quadrilateral layer of judgment on the line, but the problem of the relative position of the four points (point and point is adjacent or relative uncertainty), so need to enumerate all kinds of situations, fortunately 4 points altogether only 3 different cases: ABCD, ABDC, ACBD draw a picture can be at a glance, Next is the code, but because of some of the details of the problem I still debugging a while O (╯-╰) o

1#include <cstdio>2#include <cstring>3#include <cmath>4#include <algorithm>5 using namespacestd;6 7 structVector {8     Doublex, y;9Vector (Doublex =0,Doubley =0): X (x), Y (y) {}Ten     voidReadint () { One         intx, y; Ascanf"%d%d",&x,&y); -          This->x =x; -          This->y =y; the     } -Vectoroperator+ (ConstVector &b)Const { -         returnVector (x + b.x, y +b.y); -     } +Vectoroperator- (ConstVector &b)Const { -         returnVector (x-b.x, Y-b.y); +     } AVectoroperator* (DoublePConst { at         returnVector (x * p, Y *p); -     } -Vectoroperator/ (DoublePConst { -         returnVector (x/p, Y/p); -     } - }; in  - typedef Vector Point; totypedefConstpoint&CPoint; +typedefConstvector&Cvector; -  theVectoroperator* (DoublePConstVector &a) { *     returnAp; $ }Panax Notoginseng  - DoubleDot (Cvector A, cvector b) { the     returna.x * b.x + a.y *b.y; + } A  the DoubleLength (Cvector a) { +     returnsqrt (dot (a,a)); - } $  $ DoubleCross (Cvector A, cvector b) { -     returna.x * B.Y-A.Y *b.x; - } the  - Const DoubleEPS = 1e-Ten;Wuyi intDCMP (Doublex) { the     returnFabs (x) < EPS?0: (X <0? -1:1); - } Wu  - BOOL operator==(CPoint A, CPoint b) { About     returnDCMP (a.x-b.x) = =0&& dcmp (a.y-b.y) = =0; $ } -  - Const Chars[8][ -] = {"Ordinary quadrilateral","Trapezium","Parallelogram", -                 "Rhombus","Rectangle","Square" }; A  + intjudge (CPoint A, CPoint B, CPoint C, CPoint d) { the     if(DCMP (A-B, c-d) = =0) { -         if(DCMP (Cross (b-c, a-d)) = =0) { $             if(dcmp (Length (b-a)-Length (d-a)) = =0) { the                 if(DCMP (dot (b-a, d-a)) = =0)return 5; the                 Else    return 3; the             } the             Else if(DCMP (dot (b-a, d-a)) = =0)return 4; -             Else    return 2; in         } the         Else   return 1; the     } About     Else if(DCMP (Cross (b-c, a-d)) = =0)return 1; the     Else    return 0; the } the  + intMain () { -     intT,case =0; the Point a,b,c,d;Bayiscanf"%d",&t); the      while(t--) { the a.readint (); - b.readint (); - c.readint (); the d.readint (); theprintf"Case %d:",++Case ); the         intAns =0; theAns =Max (ans, Judge (a,b,c,d)); -Ans =Max (ans, Judge (a,b,d,c)); theAns =Max (ans, Judge (a,c,b,d)); theprintf"%s\n", S[ans]); the     }94     return 0; the}

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Calculate the geometry, or it's interesting ...

UVA 11800 determine the Shape