/in/foo.cc: In function 'void buildtree(int, int, int)':
/in/foo.cc:13:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
     int mid=l+r>>1;
             ~^~
/in/foo.cc: In function 'void modify(int, int)':
/in/foo.cc:24:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
     int mid=ll+rr>>1;
               ^