foo.cc: In function 'int main()':
foo.cc:6:6: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
  if(a>b>c)
     ~^~
foo.cc:8:6: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
  if(a>c>b)
     ~^~
foo.cc:10:6: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
  if(b>a>c)
     ~^~
foo.cc:12:6: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
  if(b>c>a)
     ~^~
foo.cc:14:6: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
  if(c>a>b)
     ~^~
foo.cc:16:6: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
  if(c>b>a)
     ~^~

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