#include<bits/stdc++.h>
using namespace std;
bool sq(vector<int> &a){
    int ver = a[0];
    for(int i = 1; i < a.size();i++){
        if(a[i] != ver) return false;
    }
    return true;
}
int main(){ 
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int t;
    cin >> t;
    while(t--){
        int n;
        cin >> n;
        vector<int> a(n);
        for(int &x : a) cin >> x;
        cout << (sq(a) ? "YES" : "NO");
        cout << "\n";
    }
}

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7
1 2 3 4
1 1 1 1
2 2 2 2
1 2 1 2
1 1 5 5
5 5 5 5
4 10 5 9