/in/foo.cc: In function 'int main()':
/in/foo.cc:44:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=0;j<son[i].size();j++){
               ~^~~~~~~~~~~~~~
/in/foo.cc:59:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(son[i].size()==m){
      ~~~~~~~~~~~~~^~~
/in/foo.cc:64:2: error: 'else' without a previous 'if'
  else{
  ^~~~
/in/foo.cc:68:7: error: 'check' was not declared in this scope
    if(check)
       ^~~~~
/in/foo.cc:69:3: error: expected primary-expression before '}' token
   }
   ^
/in/foo.cc:67:8: warning: unused variable 'mid' [-Wunused-variable]
    int mid=(l+r)>>1;
        ^~~