foo.cc:23:37: error: stray '\346' in program
                 ans1=a[i];ans2=a[j];案
                                     ^
foo.cc:23:38: error: stray '\241' in program
                 ans1=a[i];ans2=a[j];案
                                      ^
foo.cc:23:39: error: stray '\210' in program
                 ans1=a[i];ans2=a[j];案
                                       ^
foo.cc: In function 'int main()':
foo.cc:10:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
foo.cc:12:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&a[i]);
         ~~~~~^~~~~~~~~~~~

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