题解

#include<iostream>
#include<algorithm>
using namespace std;
int n,h[105],num;
bool cmp(int x,int y){
    if(x!=0 && y!=0){
        return x<y;
    }
    return x!=0;
}
int main(){
    cin>>n;
    num=n;
    for(int i=1;i<=n;i++){
        cin>>h[i];
    }
    sort(h+1,h+1+n,cmp);
    for(int i=1;i<=n;i++){
        if(h[i]==h[i+1]){
            h[i]=0;
            num--;
        }
    }
    sort(h+1,h+1+n,cmp);
    cout<<num<<endl;
    for(int i=1;i<=num;i++){
        cout<<h[i]<<" ";
    }
}