[VA] 11800-Determine the Shape (Computational ry)

[VA] 11800-Determine the Shape (Computational ry)

This question is more basic and has many methods. I use the Vector Method for computation.

Enumerate any three points to see if the three vectors identified by the three points and the fourth point constitute a parallelogram. If they are parallelogram, then judge the special graph.

14118653

11800

Determine the Shape

Accepted

C ++

0.102

2014-08-30 13:31:48

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           # Include using namespace std; const double eps = 1e-10; struct Point {double x, y; Point (double x = 0, double y = 0): x (x ), y (y) {} bool operator <(const Point & a) const {if (. x! = X) return x <. x; return y <. y ;}}; typedef Point Vector; Vector operator + (Vector A, Vector B) {return Vector (. x + B. x,. y + B. y);} Vector operator-(Point A, Point B) {return Vector (. x-B.x,. y-B.y);} Vector operator * (Vector A, double p) {return Vector (. x * p,. y * p);} Vector operator/(Vector A, double p) {return Vector (. x/p,. y/p);} int dcmp (double x) {if (fabs (x) <eps) return 0; else Return x <0? -1: 1;} bool operator = (const Point & a, const Point & B) {return dcmp (. x-b.x) = 0 & dcmp (. y-b.y) = 0;} double Dot (Vector A, Vector B) {return. x * B. x +. y * B. y;} double Dist (Point A, Point B) {return (. x-B. x) * (. x-B. x) + (. y-B. y) * (. y-B. y);} double Length (Vector A) {return sqrt (Dot (A, A);} double Angle (Vector A, Vector B) {return acos (Dot (, b)/Length (A)/Length (B);} double Cross (Vector A, Vector B) {return. x * B. y-. y * B. x;} double Area2 (Point A, Point B, Point C) {return Cross (B-A, C-A);} Vector Rotate (Vector A, double rad) {return Vector (. x * cos (rad)-. y * sin (rad),. x * sin (rad) +. y * cos (rad);} Point GetIntersection (Point P, Vector v, Point Q, Vector w) {Vector u = P-Q; double t = Cross (w, u) /Cross (v, w); return P + v * t;} bool SegmentProperIntersection (Point a1, Poin T a2, Point b1, Point b2) {double c1 = Cross (a2-a1, b1-a1), c2 = Cross (a2-a1, b2-a1); double c3 = Cross (b2-b1, a1-b1 ), c4 = Cross (b2-b1, a2-b1); return dcmp (c1) * dcmp (c2) <0 & dcmp (c3) * dcmp (c4) <0 ;} double PolygonArea (Point * p, int n) {double area = 0; for (int I = 1; I <n-1; I ++) area + = Cross (p [I]-p [0], p [I + 1]-p [0]); return area;} bool OnSegment (Point p, point a1, Point a2) {return dcmp (Cross (a1-p, A2-p) = 0 & dcmp (Dot (a1-p, a2-p) <0 ;} // Square // Rectangle // fig // Parallelogram // Trapezium trapezoid // Ordinary Quadrilateral normal Quadrilateral Point P [5]; char result [10] [30]; void init () {strcpy (result [1], "Square"); strcpy (result [2], "Rectangle "); strcpy (result [3], "Fig"); strcpy (result [4], "Parallelogram"); strcpy (result [5], "Trapezium "); strcpy (result [6], "Ordinary Quadrilateral");} int Judge (Po Int a, Point B, Point c, Point d) {Vector v1 = B-a; Vector v2 = c-a; Vector v3 = v1 + v2; if (v3 = (d-a) {// It is determined that it is a parallelogram double L1 = Dist (a, B); double L2 = Dist (a, c ); double k = Dot (v1, v2); if (! Dcmp (L1-L2 )&&! Dcmp (k) return 1; if (! Dcmp (k) return 2; if (! Dcmp (L1-L2) return 3; else return 4;} else return 0;} int Judge2 (Point a, Point B, Point c, Point d) {Vector AB = B-a; Vector bc = c-B; Vector cd = d-c; Vector da = a-d; double ans1 = Cross (AB, cd ); double ans2 = Cross (bc, da); if (! Dcmp (ans1) |! Dcmp (ans2) return 1; else return 0;} int solve () {int ans; ans = Judge (P [1], P [2], P [3], P [4]); if (ans) return ans; ans = Judge (P [1], P [3], P [4], P [2]); if (ans) return ans; ans = Judge (P [1], P [2], P [4], P [3]); if (ans) return ans; else {int OK = 0; OK = Judge2 (P [1], P [2], P [3], P [4]); if (OK) return 5; OK = Judge2 (P [1], P [3], P [4], P [2]); if (OK) return 5; OK = Judge2 (P [1], P [2], P [4], P [3]); if (OK) return 5;} return 6 ;} int main () {init (); int T, Case = 1; scanf ("% d", & T); while (T --) {for (int I = 1; I <= 4; I ++) scanf ("% lf", & P [I]. x, & P [I]. y); int ans = solve (); printf ("Case % d: % s \ n", Case ++, result [ans]);} return 0 ;}