URAL 1750 Pakhom and the Gully 计算几何+floyd
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#pragma comment(linker, "/STACK:1024000000,1024000000") #include <cstdio> #include <iostream> #include <algorithm> #include <string.h> #include <vector> #include <queue> #include <math.h> using namespace std; #define ll int #define point Point const double eps = 1e-8; const double PI = acos(-1.0); double ABS(double x){return x>0?x:-x;} int sgn(double x){ if(fabs(x) < eps)return 0; if(x<0)return -1; return 1; } struct Point { double x, y; void put(){printf("%.0f,%.0f\n",x,y);} Point(){} Point(double _x, double _y){ x = _x; y = _y; } Point operator - (const Point & b)const{ return Point(x-b.x, y-b.y); } double operator ^ (const Point &b) const{ return x*b.y - y*b.x; } double operator *(const Point &b) const{ return x*b.x + y*b.y; } void transXY(double B){ double tx = x, ty = y; x = tx*cos(B) - ty*sin(B); y = tx*sin(B) + ty*cos(B); } }; double dist(point a,point b){ return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));} struct Line { Point s,e; double len(){return dist(s,e);} Line(){} Line(Point _s, Point _e) { s = _s; e = _e; } pair<int,Point> operator & (const Line &b) const{ Point res = s; if(sgn((s-e) ^ (b.s-b.e)) == 0) { if(sgn((s-b.e) ^ (b.s-b.e)) == 0) return make_pair(0,res); else return make_pair(1,res); } double t = ((s-b.s) ^ (b.s-b.e)) / ((s-e)^(b.s-b.e)); res.x += (e.x - s.x) *t; res.y += (e.y - s.y) *t; return make_pair(2, res); } }; double cross(point a, point b, point c) { return (a.x - c.x) * (b.y - c.y) - (a.y - c.y) * (b.x - c.x); } bool intersect(Line l1, Line l2) { return max(l1.s.x, l1.e.x) > (min(l2.s.x, l2.e.x)-eps) && max(l2.s.x, l2.e.x) > (min(l1.s.x, l1.e.x)-eps) && max(l1.s.y, l1.e.y) > (min(l2.s.y, l2.e.y)-eps) && max(l2.s.y, l2.e.y) > (min(l1.s.y, l1.e.y)-eps) && (cross(l2.s, l1.e, l1.s) * cross(l1.e, l2.e, l1.s) > -eps) && (cross(l1.s, l2.e, l2.s) * cross(l2.e, l1.e, l2.s) > -eps); } bool online(Line l, point P) { return (fabs(cross(l.e, P, l.s)) < eps) && ((((P.x > l.s.x - eps) && (P.x < l.e.x + eps)) || ((P.x > l.e.x - eps) && (P.x < l.s.x+eps)))&& (((P.y > l.s.y - eps) && (P.y < l.e.y + eps)) || ((P.y > l.e.y - eps) && (P.y < l.s.y +eps)))); } bool inter(Line u, Line v){ return ((intersect(u, v)) && (!online(u, v.s)) && (!online(u, v.e)) && (!online(v, u.s)) && (!online(v, u.e))); } point S, T, A, B, C; Line AB, BC, ST, AC, SA, SB, SC, TA, TB, TC; double ans; bool ok(Line x){ if(inter(x, AB))return false; if(inter(x, BC))return false; return true; } double d[5][5]; void addedge() { for (int i=0;i<5;i++) for (int j=0;j<5;j++) { if (i==j) d[i][j]=0; else d[i][j]=1e8; } if (!inter(SA, BC)) { d[0][1]=d[1][0]=min(d[0][1],dist(S,A)); } //d[0][2]=d[2][0]=min(d[0][2],dis(S,B)); d[1][2]=d[2][1]=min(d[1][2],dist(A,B)); d[1][3]=d[3][1]=min(d[1][3],dist(A,C)); d[2][3]=d[3][2]=min(d[2][3],dist(B,C)); if (!inter(SC,AB)) { d[0][3]=d[3][0]=min(d[0][3],dist(S,C)); } if (!intersect(ST,AB) && !intersect(ST,BC)) { d[0][4]=d[4][0]=min(d[0][4],dist(S,T)); } //printf("1->4 %d\n",is_inter(A,T,B,C)); if (!inter(TA,BC)) { d[1][4]=d[4][1]=min(d[1][4],dist(A,T)); } if (cross(B,A,T)*cross(B,C,T)>-eps) { d[2][4]=d[4][2]=min(d[2][4],dist(B,T)); } if (cross(S,A,B)*cross(S,C,B)>-eps) { d[0][2]=d[2][0]=min(d[0][2],dist(S,B)); } if (!inter(TC,AB)) { d[3][4]=d[4][3]=min(d[3][4],dist(C,T)); } } int main(){ int i, j, k, cas;scanf("%d",&cas); while(cas--) { scanf("%lf %lf", &S.x, &S.y); scanf("%lf %lf", &T.x, &T.y); scanf("%lf %lf", &A.x, &A.y); scanf("%lf %lf", &B.x, &B.y); scanf("%lf %lf", &C.x, &C.y); AB = Line(A,B); BC = Line(B,C); ST = Line(S,T); AC = Line(A,C); SA = Line(S,A); SB = Line(S,B); SC = Line(S,C); TA = Line(T,A); TB = Line(T,B); TC = Line(T,C); addedge(); for(i = 0; i < 5; i++) for(j = 0; j < 5; j++) for(k = 0; k < 5; k++) d[i][j] = min(d[i][j], d[i][k]+d[k][j]); printf("%.8f\n", d[0][4]); } return 0; } /* */
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