/in/foo.cc: In function 'int main()':
/in/foo.cc:53:35: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
     int rootid = get_str_id("root");
                                   ^
/in/foo.cc:56:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if(str.length() > maxlen) {
            ~~~~~~~~~~~~~^~~~~~~~
/in/foo.cc:72:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<s.length();i++)
                     ~^~~~~~~~~~~
/in/foo.cc:73:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int j=i+1;j<s.length();j++) {
                           ~^~~~~~~~~~~
/in/foo.cc:98:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int i=0;i<s.length();i++) {
                         ~^~~~~~~~~~~
/in/foo.cc:100:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 int r = s[i==s.length()-1?0:i+1]-'0';
                           ~^~~~~~~~~~~~~~
/in/foo.cc:117:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if(s.length() < maxlen) {
            ~~~~~~~~~~~^~~~~~~~
/in/foo.cc:118:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int i=0;i<s.length()+1;i++) {
                         ~^~~~~~~~~~~~~
/in/foo.cc:120:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 int cur = s[i==s.length() ? 0:i] - '0';
                             ~^~~~~~~~~~~~
/in/foo.cc:146:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<allbian.size();i++) {
                 ~^~~~~~~~~~~~~~~