/in/foo.cc: In function 'int main()':
/in/foo.cc:44:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
         mid=l+r>>1;
             ~^~
/in/foo.cc:48:25: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
     printf("%lld\n",ans);
                         ^