C++ VP::size方法代码示例

VP ConvexCut(const VP &ps, L l) {
  VP Q;
  for (int i = 0; i < (int)ps.size(); i++) {
    P A = ps[i], B = ps[(i+1)%ps.size()];
    if (ccw(l.a, l.b, A) != -1) Q.push_back(A);
    if (ccw(l.a, l.b, A) * ccw(l.a, l.b, B) < 0)
      Q.push_back(is_ll((L){A, B}, l));
  }
  return Q;
}

void split_route(vector<Segment> &vs,VR &nodes,int idx, int n1, int n2){
   ParamEdge e=vs[idx].edge;
   debugline(e.from(),e.to(),255,0,0,true);
   double minp=DBL_MAX;
   int minidx=-1;
   for (int j=0,n=nodes.size();j<n;j++){
      if (j==n1 || j==n2) continue;
      if (e.cross(nodes[j])){
	 if (nodes[j].contains(e.from())) continue;
	 if (nodes[j].contains(e.to())) continue;
         double p=e.cross_param_smallest(nodes[j]);
         if (p<minp){
            minp=p;
            minidx=j;
         }
      }
   }
   if (minidx<0) return ;
   Point dc=e.dist_vec(nodes[minidx].center());
   if (dc.is_null()){
      dc=to_left(e.unit(),PI/2); // minidxust choose a side 
   }
   VP pts;
   Point r=e.dist_vec(nodes[minidx].TL());
   if (scalar(r,dc)<0) pts.push_back(nodes[minidx].TL());
   r=e.dist_vec(nodes[minidx].TR());
   if (scalar(r,dc)<0) pts.push_back(nodes[minidx].TR());
   r=e.dist_vec(nodes[minidx].BL());
   if (scalar(r,dc)<0) pts.push_back(nodes[minidx].BL());
   r=e.dist_vec(nodes[minidx].BR());
   if (scalar(r,dc)<0) pts.push_back(nodes[minidx].BR());
   if (pts.size()==0) {
      printf("Ups, no points on smaller side of edge/node cut area");
      return;
   }
   if (pts.size()>2 ) throw "expected 1 or 2 points";
   vector<Segment> vsnew;
   int idxlast=idx+1;
   if (pts.size()==1){
      vsnew.push_back(Segment(ParamEdge(e.from(),pts[0]),vs[idx].first,false));
      vsnew.push_back(Segment(ParamEdge(pts[0],e.to()),false,vs[idx].last));
   } else if (pts.size()==2) {
      if (norm(pts[0]-e.from())>norm(pts[1]-e.from())){ // do nearest point first
	swap(pts[0],pts[1]);
      }
      vsnew.push_back(Segment(ParamEdge(e.from(),pts[0]),vs[idx].first,false));
      vsnew.push_back(Segment(ParamEdge(pts[0],pts[1]),false,false));
      vsnew.push_back(Segment(ParamEdge(pts[1],e.to()),false,vs[idx].last));
      idxlast++;
   }
   vs.erase(vs.begin()+idx);
   vs.insert(vs.begin()+idx,vsnew.begin(),vsnew.end());
   split_route(vs,nodes,idxlast,minidx,n2);
   split_route(vs,nodes,idx,n1,minidx); // new overlaps could be introduced after makeing a kink into the line
}

ld max_distance(const VP &ps) {
  assert (ps.size() > 1);
  VP g = ConvexHull(ps);
  int n = g.size(), a = 0, b = 1;
  ld res = abs(g[0] - g[1]);
  while (a < n) {
    P p1 = g[a%n], p2 = g[(a+1)%n];
    P q1 = g[b%n], q2 = g[(b+1)%n];
    if (arg((p2 - p1) / (q1 - q2)) > 0) ++b; else ++a;
    res = max(res, abs(p1 - q1));
  }
  return res;
}

void calculatePaths() {
	for (int i = 0; i < paths.size(); i++) {
		if (paths[i].first == 1) {
			depth = 0;
			for (int j = 0; j < paths.size(); j++) {
				//cout << j << endl;
				pair<int,int> speeds = followPath(i, j);
				bessieSpeeds.pb(speeds.bessie);
				elsieSpeeds.pb(speeds.elsie);
			}
		}
	}	
}

double areaCP(VP ps, Point center, double r) {
    int n = ps.size();
    double ans = 0;
    for (int i = 0; i < n; i++) {
        ans += areaCT(ps[i], ps[(i + 1) % n], center, r);
    }
    return ans;
}

void Polygon::CreateFromPoints(const VP& SomePoints)
{
    m_pPosition = Sum(SomePoints)/SomePoints.size();

    m_vPoints = ConvexHull(SomePoints);

    for (auto& m_vPoint : m_vPoints)
    {
        m_vPoint -= m_pPosition;
    }
}

VP convexCut(VP ps, CP p1, CP p2) {
    //返回凸多边形被有向直线p1p2切割后左半部分， 可改为在线半平面交
    int n = ps.size();
    VP ret(0);
    for (int i = 0; i < n; i++) {
        int d1 = sgn((p2 - p1).det(ps[i] - p1));
        int d2 = sgn((p2 - p1).det(ps[(i + 1) % n] - p1));
        if (d1 >= 0) ret.push_back(ps[i]);
        if (d1 * d2 < 0) ret.push_back(isLL(p1, p2, ps[i], ps[(i + 1) % n])[0]);
    }
    return ret;
}

VP ConvexHull(VP ps) {
  int n = ps.size();
  int k = 0;
  sort(ps.begin(), ps.end());
  VP ch(2 * n);
  for (int i = 0; i < n; ch[k++] = ps[i++])
    while (k >= 2 && ccw(ch[k - 2], ch[k - 1], ps[i]) <= 0) --k;
  for (int i = n - 2, t = k + 1; i >= 0; ch[k++] = ps[i--])
    while (k >= t && ccw(ch[k - 2], ch[k - 1], ps[i]) <= 0) --k;
  ch.resize(k - 1);
  return ch;
}

void cut_convex(VP& a, Point p1, Point p2) {
    VP b;
    repn(i, sz(a)) {
        Point a1 = a[i], a2 = a[(i + 1) % a.size()];
        double m1 = mult(p1, p2, a1);
        double m2 = mult(p1, p2, a2);
        if(sgn(m1) * sgn(m2) < 0) {
            Point tmp;
            tmp.x = (a1.x * m2 - a2.x * m1) / (m2 - m1);
            tmp.y = (a1.y * m2 - a2.y * m1) / (m2 - m1);
            b.push_back(tmp);
        }
        if(sgn(m2) >= 0) b.push_back(a2);
    }

///********************************************************
void draw(){  //glut 回调函数
	double maxX=-100000,minX=-maxX;  
	double maxY=-100000,minY=-maxY;
	for(int i=0;i<city.size();i++){
		maxX=max(maxX,city[i].first);
		minX=min(minX,city[i].first);
		maxY=max(maxY,city[i].second);
		minY=min(minY,city[i].second);
	}
	double aveX=(minX+maxX)/2, _X=1.2*(aveX-minX);
	double aveY=(minY+maxY)/2, _Y=1.2*(aveY-minY);  //等比例缩放

	glClearColor(1.0, 1.0 , 1.0, 0); //白板
	glClear(GL_COLOR_BUFFER_BIT); //清位
	glPointSize(10); //设置点的大小,这个必须在模式选择之前
	glLineWidth(5);  //设置线宽

	glBegin(GL_POINTS);    //画点
	for(int i=0;i<city.size();i++){
		glColor3f(1,0,0);
		double x=(city[i].first-aveX)/_X;
		double y=(city[i].second-aveY)/_Y;
		glVertex2f(x,y);
	}
	glEnd();

	glBegin(GL_LINE_LOOP); //画线
	for(int i=0;i<city.size();i++){
		glColor3f(0,1,0);
		double x=(city[ permut[i] ].first- aveX)/_X; //permutation
		double y=(city[ permut[i] ].second-aveY)/_Y;
		glVertex2f(x,y);
	}
	glEnd();

	glutSwapBuffers();
}

int contains(VP ps, CP q) {
    int n = ps.size();
    int res = -1;
    for (int i = 0; i < n; i++) {
        Point a = ps[i] - q, b = ps[(i + 1) % n] - q;
        if (a.y > b.y) {
            Point t = a; a = b; b = t;
        }
        if (a.y < eps && b.y > eps && a.det(b) > eps) {
            res = -res;
        }
        if (abs(a.det(b)) < eps && a.dot(b) < eps) {
            return 0;
        }
    }
    return res;
}

double convexDiameter(VP ps) {
    int n = ps.size();
    int is = 0, js = 0;
    for (int i = 1; i < n; i++) {
        if (ps[i].x > ps[is].x) is = i;
        if (ps[i].x < ps[js].x) js = i;
    }
    double maxd = (ps[is] - ps[js]).abs();
    int i = is, j = js;
    do {
        if ((ps[(i + 1) % n] - ps[i]).det(ps[(j + 1) % n] - ps[j]) >= 0) {
            j = (j + 1) % n;
        } else {
            i = (i + 1) % n;
        }
        maxd = max(maxd, (ps[i] - ps[j]).abs());
    } while (i != is || j != js);
    return maxd;
}

double areaCT(Point p1, Point p2, double r) {
    VP qs = isCL(0, r, p1, p2);
    if (qs.size() == 0) return r * r * rad(p1, p2) / 2;
    bool b1 = p1.abs() > r + eps, b2 = p2.abs() > r + eps;
    if (b1 && b2) {
        if ((p1 - qs[0]).dot(p2 - qs[0]) < eps &&
            (p1 - qs[1]).dot(p2 - qs[1]) < eps) {
            return (r * r * (rad(p1, p2) - rad(qs[0], qs[1])) +
                qs[0].det(qs[1])) / 2;
        } else {
            return r * r * rad(p1, p2) / 2;
        }
    } else if (b1) {
        return (r * r * rad(p1, qs[0]) + qs[0].det(p2)) / 2;
    } else if (b2) {
        return (r * r * rad(qs[1], p2) + p1.det(qs[1])) / 2;
    } else {
        return p1.det(p2) / 2;
    }
}

    VP solve(VP ps) {
        int n = ps.size(), k = 0;
        if (n <= 1) {
            return ps;
        }
        sort(ps.begin(), ps.end(), cmp());

        VP qs(n * 2);
        for (int i = 0; i < n; qs[k++] = ps[i++]) {
            while(k > 1 && (qs[k - 1] - qs[k - 2]).det(ps[i] - qs[k - 1]) < eps) {
                k--;
            }
        }
        for (int i = n - 2, t = k; i >= 0; qs[k++] = ps[i--]) {
            while (k > t && (qs[k - 1] - qs[k - 2]).det(ps[i] - qs[k - 1]) < eps) {
                k--;
            }
        }

        qs.resize(k - 1);
        return qs;
    }

pair<int,int> followPath(int path, int startDepth) {
	depth++;
	if (depth > 17) return mp(1000000, 1000000);
	int bessieTime = speeds[path].bessie, elsieTime = speeds[path].elsie;
	int leastTimeBessie = 1000000, leastTimeElsie = 1000001;
	
	cout << paths[path].second << endl;
	if (paths[path].second == N - 1) {
		cout << path << endl;	
		return mp(bessieTime, elsieTime);
	}
	for (int i = startDepth; i < paths.size(); i++) {
		if (path != i && paths[path].second == paths[i].first) {
			bessieTime = speeds[path].bessie;
			elsieTime = speeds[path].elsie;
			pair<int,int> speeds = followPath(i, 0);
			bessieTime += speeds.bessie;
			elsieTime += speeds.elsie;
			if (bessieTime < leastTimeBessie) leastTimeBessie = bessieTime;
			if (elsieTime < leastTimeElsie) leastTimeElsie = elsieTime;
		}
	}	
	return mp(leastTimeBessie, leastTimeElsie);
}