/in/foo.cc: In function 'int main()':
/in/foo.cc:33:19: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int*' [-Wformat=]
   scanf("%d",&a[i]);
                   ^
/in/foo.cc:39:8: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   mid=l+r>>1;
       ~^~
/in/foo.cc:29:20: warning: unused variable 'ans' [-Wunused-variable]
  int r=0,l=1e9,mid,ans;
                    ^~~