/in/foo.cc:3:16: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
 #define N 1<<11+5
              ~~^~
/in/foo.cc:5:10: note: in expansion of macro 'N'
 int n,ch[N],len;
          ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:29:13: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
  len = (1<<n+1)-1;
            ~^~
/in/foo.cc:30:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<s.size();i++) ch[len-i] = s[s.size()-1-i]-'0'; 
              ~^~~~~~~~~