HDU3694 Fermat Point in quadrangle (for quadrilateral fee)

Test instructions: Give a four-sided shape, ask a point to the quadrilateral four points distance and the minimum distance and how much.

Analysis: If the convex quadrilateral, Ferma is the diagonal intersection, the distance is the diagonal length.

If it is a concave polygon, the Ferma is the concave point.

#include <iostream>#include<cstdio>#include<cstring>#include<string>#include<cmath>#include<cstdlib>#include<queue>#include<stack>#include<map>#include<vector>#include<algorithm>#include<ctime>using namespacestd;#defineEPS 1e-8intFabs (Doubled) {    if(Fabs (d) <eps)return 0; Else returnD>0?1:-1;}structpoint{Doublex, y;} p[Ten],sta[Ten];intoper[8][2]={0,1,0,-1,-1,0,1,0,1,1,1,-1,-1,1,-1,-1},top;DoubleX_multi (Point p1,point p2,point p3) {return(p2.x-p1.x) * (P3.Y-P1.Y)-(p3.x-p1.x) * (p2.y-p1.y);}DoubleDis (Point p1,point p2) {returnsqrt ((p1.x-p2.x) * (p1.x-p2.x) + (P1.Y-P2.Y) * (p1.y-p2.y));}BOOLCMP (point A,point b) {if(Fabs (X_multi (p[0],A,B)) >0)return 1; if(Fabs (X_multi (p[0],A,B)) <0)return 0; if(Fabs (Dis (p[0],a)-dis (p[0],B)) <0)        return 1; return 0;}voidGraham (intN) {    inti,k=0, tot;  for(i=1; i<n;i++)        if((P[I].Y&LT;P[K].Y) | | ((P[I].Y==P[K].Y) && (p[i].x<p[k].x)))  K=i; Swap (p[0],p[k]); Sort (P+1, p+n,cmp); sta[0]=p[0],sta[1]=p[1]; I=top=1;  for(i=2; i<n;i++)    {         while(top>=1&&fabs (X_multi (p[i],sta[top],sta[top-1])) >=0)        {            if(top==0) Break; Top--; } sta[++top]=P[i]; }}intMain () {inti,j;  while(~SCANF ("%LF%LF%LF%LF%LF%LF%LF%LF", &p[0].x,&p[0].y,&p[1].x,&p[1].y,&p[2].x,&p[2].y,&p[3].x,&p[3].y)) {if(p[0].x==-1&&p[0].y==-1&&p[1].x==-1&&p[1].y==-1&&p[2].x==-1&&p[2].y==-1&&p[3].x==-1&&p[3].y==-1)             Break; Graham (4); Doubleans; if(top==3) ans=dis (sta[0],sta[2]) +dis (sta[1],sta[3]);//convex quads directly take diagonal intersections        Else{ans=1e50; Doublesum=0;  for(i=0;i<4; i++) {sum=0.0;  for(j=0;j<4; j + +)                    if(i!=j) Sum+=Dis (P[i],p[j]); Ans=min (Sum,ans); }} printf ("%.4lf\n", ans); }    return 0;}

HDU3694 Fermat Point in quadrangle (for quadrilateral fee)