BZOJ1074 [SCOI2007] Origami Origami

Original Address http://www.cnblogs.com/Christopher-Cao/p/5482575.html

This problem is a bare question of computational geometry. It seems to be folded a few times to use something to maintain, in fact, because n<=8 so can be violent statistics. The only difficult thing is to find the point of the symmetry point (in fact, there is no difficulty it)

Paste Code

1#include <cstdio>2#include <cmath>3#include <vector>4 using namespacestd;5 6 Const intMAXN =Ten ; 7 Const intMAXM = - ; 8 Const DoubleEPS = 1e-6 ; 9 intN, M;Ten  One structPoint { A     Doublex, y; -Point (Const DoubleXConst Doubley): - x (x), Y (y) {}; the } ;  -  - structVector { -     Doublex, y; +Vector (Const DoubleXConst Doubley): - x (x), Y (y) {}; + } ;  A  at structLine { - Point from , to; -Line (Const DoubleX1,Const DoubleY1, -            Const DoubleX2,Const Doubley2): - From (x1, y1), to (x2, y2) {}; -Vector Tovector ()Const ; in } ; -  toVectoroperator- (ConstPoint & First,ConstPoint &Second) { +     returnVector (First X-second x, first Y-Second. Y);  - }  the  *Pointoperator- (ConstPoint & First,ConstVector &Second) { $     returnPoint (First X-second x, first Y-Second. Y); Panax Notoginseng }  -  theVectoroperator* (Const DoubleKConstVector &Input) { +     returnVector (k * Input. x, K *Input. Y);  A } the  +Pointoperator+ (ConstPoint & First,ConstVector &Second) { -     returnPoint (First x + Second. x, first y +Second. Y);  $ } $  - //above is the definition of vectors and various addition and subtraction operations - Double operator^ (ConstVector & First,ConstVector &Second) { the     returnFirst. X * Second. Y-first. Y *Second. x; - }  Wuyi //Cross Product the Double operator* (ConstVector & First,ConstVector &Second) { -     returnFirst. X * Second. x + first. Y *Second. Y; Wu } - //Inner Product About DoubleABS (ConstVector &Input) { $     returnsqrt (input. x * input. x + input. Y *Input. Y);  - } - //die -Vector Line:: Tovector ()Const{returnTo-from ;}  A  +Vector < line >Opts; the  -Point Reflect (ConstPoint O,ConstLine L) { $     Const DoubleDis = ((L). From-o) ^ (L. To-o))/ABS (L. Tovector ()); the     ConstVector Lp =1.0/abs (L. tovector ()) *L. Tovector (); the     returnO +2.0* Dis * Vector (Lp. Y,-Lp. x); the } the  - intQuery (ConstPoint O,Const intT) { in     //printf ("Dfs%.2lf%.2lf%d\n",o.x,o.y,t); the     if(T = =-1 )  the         return(EPS <= o. x && o. x <=100.0-EPS) && About(eps <= o. y && o. Y <=100.0-EPS);  the     //This place did not add EPS at first, so WA (conscience example) the     Const DoubleCrossvalue = the(Opts [T]. From-o) ^ (Opts [T]. To-o)); +     if(Crossvalue <-EPS)return 0 ;  -     if(-EPS <= crossvalue && crossvalue <= EPS)return 0 ;  the     //This place is more a row because at the beginning of the reading of the problem when the boundary is counted only once, and then did not have a sample to understand the boundary does not countBayi     returnQuery (O, T-1) + theQuery (Reflect (o, Opts [t]), T-1 ) ;  the } -  - intMain () { thescanf ("%d", &N);  the      for(inti =0; i < N; ++i) { the         Doublex1, y1, x2, y2; thescanf ("%LF%LF%LF%LF", & X1, & Y1, & x2, &y2);  - Opts. Push_back (Line (x1, y1, x2, y2)); the     }  thescanf ("%d", &M);  the      while(M-- ) {94         Doublex, y; thescanf ("%LF%LF", & X, &y);  theprintf ("%d\n", Query (Point (x, y), N-1 ) ) ; the     }98     return 0 ; About}

BZOJ1074 [SCOI2007] Origami Origami