uva 10256 - The Great Divide
当退化成点和线段的时候，可以不进行特判；
因为这种情况已经包括进条件1.2里面了
1 #include <cstdio> 2 #include <cmath> 3 #include <cstring> 4 #include <algorithm> 5 #include <vector> 6 #define eps 1e-9 7 using namespace std; 8 const double pi = acos(-1); 9 10 int dcmp(double x) 11 { 12 return fabs(x) < eps ? 0 : (x > 0 ? 1 : -1); 13 } 14 15 struct Point 16 { 17 double x; 18 double y; 19 20 Point(double x = 0, double y = 0):x(x), y(y) {} 21 22 bool operator < (const Point& e) const 23 { 24 return dcmp(x - e.x) < 0 || (dcmp(x - e.x) == 0 && dcmp(y - e.y) < 0); 25 } 26 27 bool operator == (const Point& e) const 28 { 29 return dcmp(x - e.x) == 0 && dcmp(y - e.y) == 0; 30 } 31 }; 32 33 typedef Point Vector; 34 35 Vector operator + (Point A, Point B) 36 { 37 return Vector(A.x + B.x, A.y + B.y); 38 } 39 40 Vector operator - (Point A, Point B) 41 { 42 return Vector(A.x - B.x, A.y - B.y); 43 } 44 45 Vector operator * (Point A, double p) 46 { 47 return Vector(A.x * p, A.y * p); 48 } 49 50 Vector operator / (Point A, double p) 51 { 52 return Vector(A.x / p, A.y / p); 53 } 54 double dot(Point a,Point b){return a.x*b.x+a.y*b.y;} 55 double cross(Point a,Point b){return a.x*b.y-a.y*b.x;} 56 Point rotate(Point a,double ang){return Point(a.x*cos(ang)-a.y*sin(ang),a.x*sin(ang)+a.y*cos(ang));} 57 int convexhull(Point *p,int n,Point *ch) 58 { 59 sort(p,p+n); 60 int m=0; 61 for(int i=0;i<n;i++) 62 { 63 while(m>1&&cross(ch[m-1]-ch[m-2],p[i]-ch[m-2])<=0)m--; 64 ch[m++]=p[i]; 65 } 66 int k=m; 67 for(int i=n-2;i>=0;i--) 68 { 69 while(m>k&&cross(ch[m-1]-ch[m-2],p[i]-ch[m-2])<=0)m--; 70 ch[m++]=p[i]; 71 } 72 if(n>1)m--; 73 return m; 74 } 75 bool onsegment(Point p,Point a,Point b) 76 { 77 return dcmp(cross(a-p,b-p))==0&&dcmp(dot(a-p,b-p))<0; 78 } 79 80 81 bool SegmentProperIntersection( Point a1, Point a2, Point b1, Point b2 ) //线段相交，交点不在端点 82 { 83 double c1 = cross( a2 - a1, b1 - a1 ), c2 = cross( a2 - a1, b2 - a1 ), 84 c3 = cross( b2 - b1, a1 - b1 ), c4 = cross( b2 - b1, a2 - b1 ); 85 return dcmp(c1)*dcmp(c2) < 0 && dcmp(c3) * dcmp(c4) < 0; 86 } 87 88 int ispointinpolygon(Point p,int n,Point *poly) 89 { 90 int wn=0; 91 for(int i=0;i<n;i++) 92 { 93 if(onsegment(p,poly[i],poly[(i+1)%n]))return -1; 94 int k=dcmp(cross(poly[(i+1)%n]-poly[i],p-poly[i])); 95 int d1=dcmp(poly[i].y-p.y); 96 int d2=dcmp(poly[(i+1)%n].y-p.y); 97 if(k>0&&d1<=0&&d2>0)wn++; 98 if(k<0&&d2<=0&&d1>0)wn--; 99 } 100 if(wn!=0)return 1; 101 return 0; 102 } 103 104 bool Check(int n,Point *ch,int m,Point *th) 105 { 106 for(int i=0;i<n;i++) 107 { 108 if(ispointinpolygon(ch[i],m,th)!=0)return 1; 109 } 110 for(int i=0;i<m;i++) 111 if(ispointinpolygon(th[i],n,ch)!=0)return 1; 112 ch[n]=ch[0]; 113 th[m]=th[0]; 114 for(int i=0;i<n;i++) 115 for(int j=0;j<m;j++) 116 if(SegmentProperIntersection(ch[i],ch[i+1],th[j],th[j+1]))return 1; 117 return 0; 118 } 119 120 Point p[1009],ch[1009]; 121 Point q[1009],th[1009]; 122 int main() 123 { 124 int n,m; 125 while(scanf("%d%d",&n,&m)&&(n+m)) 126 { 127 for(int i=0;i<n;i++) 128 scanf("%lf%lf",&p[i].x,&p[i].y); 129 for(int i=0;i<m;i++) 130 scanf("%lf%lf",&q[i].x,&q[i].y); 131 int n1=convexhull(p,n,ch); 132 int m1=convexhull(q,m,th); 133 if(Check(n1,ch,m1,th))puts("No"); 134 else puts("Yes"); 135 } 136 return 0; 137 }
