/in/foo.cc: In function 'int main()':
/in/foo.cc:11:21: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int*' [-Wformat=]
  while(scanf("%d",&n)!=EOF)
                   ~~^
/in/foo.cc:16:21: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int*' [-Wformat=]
    scanf("%d",&x1[i]);
               ~~~~~~^
/in/foo.cc:32:24: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long long int' [-Wformat=]
   printf("%d\n",x2[k/2]);
                 ~~~~~~~^