xmu 1228

#include<iostream>  #include<cmath>  #include<time.h>  using namespace std;  #define N 1000000  double Randomf(double a, double b)  {      double c;      c = (double)(a+(b-a)*1.0*rand()/RAND_MAX);      return c;  }  int Randomi(int a, int b)  {      int c;      c=(int)Randomf((double)a,(double)b);      return c;  }    int main()  {      int n ;      cin>>n;      srand((unsigned)time(NULL) );      double x[10],y[10],r[10];      double a,b;      int cnt=0;      for(int i=0;i<n;i++)      {          cin>>x[i]>>y[i]>>r[i];      }      for(int i=1;i<=N;i++)      {          a=Randomf(0,1);          b=Randomf(0,1);          for(int j=0;j<n;j++)          {              double L=sqrt((a-x[j])*(a-x[j])+(b-y[j])*(b-y[j]));              if(L<=r[j])              {                  cnt++;                  break;              }          }      }      printf("%lf\n",(double)cnt*1.0/N);      return 0;  }