foo.cc: In function 'int main()':
foo.cc:29:21: error: cannot bind non-const lvalue reference of type 'int&' to an rvalue of type 'int'
   scan(a,begin,t,p,q);
                     ^
foo.cc:4:6: note:   initializing argument 4 of 'void scan(std::__cxx11::string, int, int, int&, int&)'
 void scan(string a,int begin,int t,int &p,int &q){
      ^~~~
foo.cc:35:29: error: cannot bind non-const lvalue reference of type 'int&' to an rvalue of type 'int'
  scan(a,begin,a.length(),p,q);
                             ^
foo.cc:4:6: note:   initializing argument 4 of 'void scan(std::__cxx11::string, int, int, int&, int&)'
 void scan(string a,int begin,int t,int &p,int &q){
      ^~~~
foo.cc:43:21: error: cannot bind non-const lvalue reference of type 'int&' to an rvalue of type 'int'
   scan(a,begin,t,p,q);
                     ^
foo.cc:4:6: note:   initializing argument 4 of 'void scan(std::__cxx11::string, int, int, int&, int&)'
 void scan(string a,int begin,int t,int &p,int &q){
      ^~~~
foo.cc:49:29: error: cannot bind non-const lvalue reference of type 'int&' to an rvalue of type 'int'
  scan(a,begin,a.length(),p,q);
                             ^
foo.cc:4:6: note:   initializing argument 4 of 'void scan(std::__cxx11::string, int, int, int&, int&)'
 void scan(string a,int begin,int t,int &p,int &q){
      ^~~~

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