foo.cc: In function 'int main()':
foo.cc:42:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<s.size();i++){
              ~^~~~~~~~~
foo.cc:43:13: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(bd[s[i]]){
             ^
foo.cc:44:17: warning: array subscript has type 'char' [-Wchar-subscripts]
    if(!bd[s[i-1]])hz+='.';
                 ^
foo.cc:45:14: warning: array subscript has type 'char' [-Wchar-subscripts]
    if(bd[s[i]]==1)st2.push(s[i]);
              ^
foo.cc:46:19: warning: array subscript has type 'char' [-Wchar-subscripts]
    else if(bd[s[i]]==5){ 
                   ^
foo.cc:56:38: warning: array subscript has type 'char' [-Wchar-subscripts]
      while(!st2.empty()&&bd[st2.top()]>=bd[s[i]])
                                      ^
foo.cc:56:48: warning: array subscript has type 'char' [-Wchar-subscripts]
      while(!st2.empty()&&bd[st2.top()]>=bd[s[i]])
                                                ^
foo.cc:56:6: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
      while(!st2.empty()&&bd[st2.top()]>=bd[s[i]])
      ^~~~~
foo.cc:58:7: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
       st2.pop();
       ^~~
foo.cc:64:3: error: 'else' without a previous 'if'
   else hz+=s[i];
   ^~~~
foo.cc:64:14: error: 'i' was not declared in this scope
   else hz+=s[i];
              ^
foo.cc: At global scope:
foo.cc:66:2: error: expected unqualified-id before 'if'
  if(!bd[s[s.size()-1]])hz+='.';
  ^~
foo.cc:67:2: error: expected unqualified-id before 'while'
  while(!st2.empty()){ 
  ^~~~~
foo.cc:71:2: error: 'hz' does not name a type
  hz+="@";
  ^~
foo.cc:72:2: error: expected unqualified-id before 'for'
  for(int i=0;i<hz.size();i++){
  ^~~
foo.cc:72:14: error: 'i' does not name a type
  for(int i=0;i<hz.size();i++){
              ^
foo.cc:72:26: error: 'i' does not name a type
  for(int i=0;i<hz.size();i++){
                          ^
foo.cc:83:2: error: 'cout' does not name a type; did you mean 'cosl'?
  cout<<a.top();
  ^~~~
  cosl
foo.cc:84:2: error: expected unqualified-id before 'return'
  return 0; 
  ^~~~~~
foo.cc:86:1: error: expected declaration before '}' token
 }
 ^

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