/in/foo.cc: In function 'void dfs(int)':
/in/foo.cc:30:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(f[nex]==0 &&dist(sta,nex)<=4*r*r){   
                  ~~~~~~~~~~~~~^~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:40:15: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int*' [-Wformat=]
  scanf("%d",&T);
             ~~^
/in/foo.cc:37:6: warning: unused variable 'a' [-Wunused-variable]
  int a,b,c;
      ^
/in/foo.cc:37:8: warning: unused variable 'b' [-Wunused-variable]
  int a,b,c;
        ^
/in/foo.cc:37:10: warning: unused variable 'c' [-Wunused-variable]
  int a,b,c;
          ^