为什么错？？？！！！

#include<bits/stdc++.h> using namespace std; int main(){ freopen("A.in","r",stdin); freopen("A.out","w",stdout); int n,a[10000]; cin>>n; for(int i=1;i<=n;i++){ cin>>a[i]; } sort(a+1,a+1+n); for(int i=1;i<=n;i++){ cout<<a[i]<<" "; } cout<<endl; int m=unique(a+1,a+1+n)-a; cout<<m-1<<endl; for(int i=1;i<m;i++){ cout<<a[i]<<" "; } return 0; }