/in/foo.cc:8:12: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
 char s[1<<N+5];
            ^
/in/foo.cc:9:17: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
 char* tree[(1<<N+1)+5];
                 ^
/in/foo.cc: In function 'void post(char*, int)':
/in/foo.cc:20:14: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
  if(id>=(1<<n+1)-1) return;
             ~^~
/in/foo.cc: In function 'int main()':
/in/foo.cc:30:14: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
  char fb[1<<n+1];
             ~^~
/in/foo.cc:31:22: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
  for(int i=0;i+1<1<<n+1;i++){
                     ~^~