foo.cc: In function 'dd ch(double)':
foo.cc:60:20: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
                 if (fa[u]!=edge[i].to)
                    ^
foo.cc: In function 'int main()':
foo.cc:124:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~
foo.cc:129:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&u,&v);
         ~~~~~^~~~~~~~~~~~~~
foo.cc:135:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lf",&p);
     ~~~~~^~~~~~~~~~

自豪的采用 HydroJudge 进行评测(github.com/hydro-dev/HydroJudge)

{"receive":"2020-07-08T13:28:25.989Z","handle":"2020-07-08T13:28:25.989Z","cache_start":"2020-07-08T13:28:25.996Z","read_cases":"2020-07-08T13:28:26.106Z","judge":"2020-07-08T13:28:26.107Z","done":"2020-07-08T13:28:27.329Z"}