/in/foo.cc: In function 'll Bin_search()':
/in/foo.cc:39:16: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
     ll mid = l + r >> 1;
              ~~^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:51:12: error: 'len' was not declared in this scope
   d[++n] = len;
            ^~~