foo.cc: In function 'int main()':
foo.cc:33:19: warning: unused variable 'min' [-Wunused-variable]
         int xa,ya,min;
                   ^~~
foo.cc:42:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0;i<arr.size();i++){
                  ~^~~~~~~~~~~
foo.cc:31:9: warning: unused variable 'ans1' [-Wunused-variable]
     int ans1=0,ans2=0;
         ^~~~
foo.cc:31:16: warning: unused variable 'ans2' [-Wunused-variable]
     int ans1=0,ans2=0;
                ^~~~

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