2017 ACM-ICPC 亚洲区(南宁赛区)网络赛: G. Finding the Radius for an Inserted Circle(笛卡尔定理)
ThreecirclesCa,Cb,andCc,allwithradiusRandtangenttoeachother,arelocatedintwo-dimensionalspaceasshowninFigure1.AsmallercircleC1withradiusR1(R1usingnamespacestd;constdoublePI=3.14159;intmain(){intT,n;dou