rt，本人全哇（wa）（用了最朴素的过了样例。。。）

码：

#include<iostream>
#include<algorithm> 
#include<cstring>
#define ll long long
using namespace std;
ll n,i,t,j;
struct node{
	ll v,id;
};
node a[100005],b[100005];
bool cmp1(node x,node y){
	return x.v<y.v;
}
bool cmp2(node x,node y){
	return x.id<y.id;
}
int main()
{
	cin>>t;
	for(i=1;i<=t;i++){
		memset(a,0,sizeof(a));
		memset(b,0,sizeof(b));
		cin>>n;
		ll tmp=1;
		for(j=1;j<=n;j++){
			cin>>a[j].v;
			a[j].id=j;
		}
		sort(a+1,a+n+1,cmp1);
		for(j=1;j<=n;j++){
			b[tmp].id=a[j].id,b[tmp++].v=a[j].v;
			while(a[j+1].v==a[j].v)j++;
		}
		sort(b+1,b+tmp,cmp2);
		for(j=1;j<tmp;j++)
			cout<<b[j].v<<" ";
		cout<<endl;
	}
}