此題用桶肯定行不通
所以果斷選擇用\(MAP\)
不過看標簽貌似是\(hash\) 反正我用桶做的

#include <bits/stdc++.h>
#define Abs(x) x?x:-x
#define Max(a,b) a>b?a:b
#define Min(a,b) a<b?a:b
#define f(i,j,n) for(register int i=j;i<=n;i++)
#define F(i,j,n) for(register int i=j;i>=n;i--)
using namespace std;
typedef long long ll;
int t;
int n;
map<int , bool>mp;
namespace solve{
    inline ll read() { ll x=0,f=1; char ch=getchar();
        while(!isdigit(ch)) (ch=='-')&(f=-1),ch=getchar();
        while(isdigit(ch)) x=(x<<1)+(x<<3)+(ch^48),ch=getchar(); return x*f;
    }
    template <typename T> inline void Write(T x) {
        if(x<0)(putchar('-'),x=-x);
        if(x>9)(Write(x/10)); putchar(x%10+'0'); return ;
    }
    template <typename X,typename Y> inline ll Gcd(X x,Y y) {return y?Gcd(y,x%y):x;}
    template <typename X,typename Y> inline ll Lcd(X x,Y y) {return x*y/Gcd(x,y);}
    void Main(){
        #ifdef Open
        freopen(".in","r",stdin),freopen(".out","w",stdout);
        #endif
        ios::sync_with_stdio(false),cin.tie(0);
        mp.clear();
        t=read();
        while (t-- ){ n=read();mp.clear();
            f(i,1,n) {
                int x=read();
                if(!mp[x]) Write(x),putchar(' ');
                mp[x]=true;
            }
            puts("");
        }
    }
};
signed main() {return solve::Main(),0;}
 

$P4305 [JLOI2011]不重復數字$