三角形外接圆圆心
Where is the little Jgshining?
#include<bits/stdc++.h> using namespace std; double xx1,yy1,xx2,yy2,xx3,yy3; int main( ) { int t; scanf("%d",&t); while(t--) { scanf("%lf%lf%lf%lf%lf%lf",&xx1,&yy1,&xx2,&yy2,&xx3,&yy3); if(xx3==xx1&&yy3==yy1) { printf("%.1lf %.1lf\n",xx1+xx2/2,yy1+yy2/2); } else if(yy2==yy3&&xx2==xx3) { printf("%.1lf %.1lf\n",xx1+xx2/2,yy1+yy2/2); } else if(yy2==yy1&&xx2==xx1) { printf("%.1lf %.1lf\n",xx1+xx3/2,yy1+yy3/2); } else if(((xx3-xx2)*(yy2-yy1)-(xx2-xx1)*(yy3-yy2))==0) { printf("No this position\n"); } else { double a=((yy2-yy1)*(yy3*yy3-yy1*yy1+xx3*xx3-xx1*xx1)-(yy3->yy1)*(yy2*yy2-yy1*yy1+xx2*xx2-xx1*xx1))/(2.0*((xx3-xx1)*(yy2-yy1)-(xx2->xx1)*(yy3-yy1))); double b=((xx2-xx1)*(xx3*xx3-xx1*xx1+yy3*yy3-yy1*yy1)-(xx3->xx1)*(xx2*xx2-xx1*xx1+yy2*yy2-yy1*yy1))/(2.0*((yy3-yy1)*(xx2-xx1)-(yy2->yy1)*(xx3-xx1))); double r=sqrt((xx1-a)*(xx1-a)+(yy1-b)*(yy1-b)); printf("%.1lf %.1lf\n",a,b); } } return 0; }
