foo.cc:34:9: error: 'pair' does not name a type; did you mean 'wait'?
 typedef pair<double,double> dd;
         ^~~~
         wait
foo.cc:35:9: error: 'pair' does not name a type; did you mean 'wait'?
 typedef pair<int,int> ii;
         ^~~~
         wait
foo.cc:46:1: error: 'ii' does not name a type; did you mean 'fi'?
 ii e[3];
 ^~
 fi
foo.cc:51:1: error: 'dd' does not name a type
 dd ch(double ans) {
 ^~
foo.cc:100:1: error: 'dd' does not name a type
 dd check(double ans) {
 ^~
foo.cc: In function 'int main()':
foo.cc:129:14: error: 'e' was not declared in this scope
         else e[l++]=ii(u,v);
              ^
foo.cc:129:21: error: 'ii' was not declared in this scope
         else e[l++]=ii(u,v);
                     ^~
foo.cc:129:21: note: suggested alternative: 'i'
         else e[l++]=ii(u,v);
                     ^~
                     i
foo.cc:135:21: error: 'check' was not declared in this scope
         double last=check(0).first;
                     ^~~~~
foo.cc:135:21: note: suggested alternative: 'clock'
         double last=check(0).first;
                     ^~~~~
                     clock
foo.cc:140:5: error: 'dd' was not declared in this scope
     dd ans;
     ^~
foo.cc:144:9: error: 'ans' was not declared in this scope
         ans=check(last);
         ^~~
foo.cc:144:9: note: suggested alternative: 'abs'
         ans=check(last);
         ^~~
         abs
foo.cc:144:13: error: 'check' was not declared in this scope
         ans=check(last);
             ^~~~~
foo.cc:144:13: note: suggested alternative: 'clock'
         ans=check(last);
             ^~~~~
             clock
foo.cc:122:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~
foo.cc:127:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&u,&v);
         ~~~~~^~~~~~~~~~~~~~
foo.cc:133:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lf",&p);
     ~~~~~^~~~~~~~~~

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