/in/foo.cc: In function 'void preprocess()':
/in/foo.cc:36:20: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
     int l = 1 << k + 1;
                  ~~^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:73:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
       int mid = l + r >> 1;
                 ~~^~~