Cross product judgment POJ1696

1 //Cross product judgment POJ16962 3#include <iostream>4#include <algorithm>5#include <cstring>6#include <cstdio>7#include <vector>8#include <cmath>9#include <map>Ten using namespacestd; One #defineLL Long Long Atypedef pair<int,int>PII; - Const DoubleINF =123456789012345.0; - Const intMOD =998244353; the Const intN = 2e5+Ten; - Const intMaxx =200010;  - #defineCLC (A, B) memset (A,b,sizeof (a)) - Const DoubleEPS = 1e-8; + voidFre () {freopen ("In.txt","R", stdin);} - voidFreout () {freopen ("OUT.txt","W", stdout);} +InlineintRead () {intx=0, f=1;CharCh=getchar (); while(ch>'9'|| ch<'0') {if(ch=='-') f=-1; Ch=getchar ();} while(ch>='0'&&ch<='9') {x=x*Ten+ch-'0'; Ch=getchar ();}returnx*F;} A  at intSgnDoublex) { -     if(Fabs (x) < EPS)return 0; -     if(X <0)return-1; -     Else return 1; - } -  in structpoint{ -     Doublex, y; to     intindex; + Point () {} -Point (Double_x,Double_y) { thex = _x;y =_y; *     } $Pointoperator-(ConstPoint &b)Const{Panax Notoginseng         returnPoint (X-b.x,y-b.y); -     } the     Double operator^(ConstPoint &b)Const{ +         returnx*b.y-y*b.x; A     } the     Double operator*(ConstPoint &b)Const{ +         returnx*b.x + y*b.y; -     } $ }; $  - DoubleDist (Point A,point b) { -     returnsqrt (A-B) * (Ab)); the } - Wuyi intPos; thePoint p[ the]; - BOOLCMP (point A,point b) { Wu     DoubleTmp= (A-p[pos]) ^ (b-P[pos]); -     if(SGN (tmp) = =0){ About         returnDist (A,p[pos]) <Dist (B,p[pos]); $     } -     Else if(SGN (TMP) <0)return false; -     Else return true; - } A  + intMain () { the     intT,n; -scanf"%d",&T); $      while(t--){ thescanf"%d",&n); the          for(intI=0; i<n;i++){ thescanf"%D%LF%LF",&p[i].index,&p[i].x,&p[i].y); the             if(p[i].y<p[0].y| | (p[i].y==p[0].y&&p[i].x<p[0].x)) { -Swap (p[i],p[0]); in             } the         } thepos=0; About          for(intI=0; i<n;i++){ theSort (p+i,p+n,cmp); thepos++; the         } +printf"%d", n); -          for(intI=0; i<n;i++) theprintf"%d", P[i].index);Bayiprintf"\ n"); the     } the     return 0; -}

Cross product judgment POJ1696