/in/foo.cc: In function 'int main()':
/in/foo.cc:30:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(i=0;i<com.size();i++){
           ~^~~~~~~~~~~
/in/foo.cc:48:12: warning: array subscript has type 'char' [-Wchar-subscripts]
     if(v[it]){
            ^
/in/foo.cc:62:21: warning: array subscript has type 'char' [-Wchar-subscripts]
     s[++top]=it,v[it]=1;
                     ^
/in/foo.cc:67:13: warning: array subscript has type 'char' [-Wchar-subscripts]
     v[s[top]]=0;
             ^
/in/foo.cc:77:8: warning: 'o' may be used uninitialized in this function [-Wmaybe-uninitialized]
   else if(o==now)printf("Yes\n");else printf("No\n");
        ^~