foo.cc: In function 'int main()':
foo.cc:21:22: warning: 'x' is used uninitialized in this function [-Wuninitialized]
  for(int i=0;i<Unique(a,n,x);i++)
                ~~~~~~^~~~~~~
/tmp/ccEv01XK.o: In function `main':
foo.cc:(.text.startup+0xe8): undefined reference to `Output(int*, int)'
foo.cc:(.text.startup+0x110): undefined reference to `Output(int*, int)'
collect2: error: ld returned 1 exit status

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