POJ 1066 Treasure Hunt

Enumeration + Judging segment intersection

#include <cstdio>#include<cmath>#include<cstring>#include<cmath>#include<algorithm>#include<map>#include<vector>using namespacestd;Const intinf=0x7FFFFFFF;Const intmaxn= -+Ten;#defineEPS 1e-8intN,ans,num;Doublepx,py;structline{DoubleSx,sy; DoubleEx,ey;} L[MAXN];structpoint{Doublex; Doubley; Point (DoubleADoubleb) {x=A; Y=b; }};DoubleCross_pro (Point p0, point P1, point p2) {return(p1.x-p0.x) * (P2.Y-P0.Y)-(p2.x-p0.x) * (p1.y-p0.y);}intDBLCMP (Doubled) {    if(Fabs (d) <EPS)return 0; return(D >0) ?1: -1;}BOOLIs_intersect (Point P1, point P2, point P3, point P4) {returnDBLCMP (Cross_pro (P3, P4, p1)) * DBLCMP (Cross_pro (P3, P4, p2)) = =-1;}intMain () { while(~SCANF ("%d",&N)) {ans=INF;  for(intI=1; i<=n; i++) scanf ("%LF%LF%LF%LF", &l[i]. Sx,&l[i]. Sy,&l[i]. ex,&L[i].        Ey); scanf ("%LF%LF",&px,&Py);  for(intI=1; i<=n; i++) {point A (L[i]. Sx,l[i].            Sy);            Point B (Px,py); Num=0;  for(intj=1; j<=n; J + +) {point C (l[j]. SX,L[J].                Sy); Point D (L[j]. EX,L[J].                Ey); if(Is_intersect (a,b,c,d)) num++; } ans=min (ans,num); Point AA (L[i]. Ex,l[i].            Ey);            Point BB (Px,py); Num=0;  for(intj=1; j<=n; J + +) {point C (l[j]. SX,L[J].                Sy); Point D (L[j]. EX,L[J].                Ey); if(Is_intersect (aa,bb,c,d)) num++; } ans=min (ans,num); }        if(n==0) printf ("Number of doors = 1\n"); Elseprintf"Number of doors =%d\n", ans+1); }    return 0;}

POJ 1066 Treasure Hunt