foo.cc: In function 'int main()':
foo.cc:8:16: warning: unused variable 'out' [-Wunused-variable]
  int a[n],k[m],out[n];
                ^~~
foo.cc:28:12: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<ans+1<<endl;
            ^

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