foo.cc: In function 'int main()':
foo.cc:9:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(int i=a; i<b; i++) 
  ^~~
foo.cc:23:3: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   cout<<cnt;
   ^~~~

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