foo.cc:28:18: error: empty character constant
 if(ch[node][S[i]-'']){
                  ^~
foo.cc:29:20: error: empty character constant
 node=ch[node][S[i]-''];
                    ^~
foo.cc: In function 'int main()':
foo.cc:162:37: warning: operation on 'cntQ' may be undefined [-Wsequence-point]
 scanf("%d%d",&Query[cntQ][0],&Query[++cntQ][1]);
                                     ^~~~~~
foo.cc:160:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d",&Q);
 ~~~~~^~~~~~~~~
foo.cc:162:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d%d",&Query[cntQ][0],&Query[++cntQ][1]);
 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc: In member function 'void A_Cautomation::Insert()':
foo.cc:23:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%s",S);
 ~~~~~^~~~~~~~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。