A.cpp

#include <bits/stdc++.h>
 
using namespace std;
 
#define int long long int
#define double long double
     
#define vi vector<int>
#define mii map<int, int>
#define pii pair<int, int>
#define vii vector<pii>
 
#define ff first
#define ss second
#define pb push_back
#define ppb pop_back()
#define in insert
#define lb lower_bound
#define ub upper_bound
#define fr front()
#define bk back()
#define make make_pair
#define size(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define repp(i, a, b, c) for (int i = a; i < b; i += c)
#define bckk(i, a, b, c) for (int i = a - 1; i >= b; i -= c)
#define rep(i, a, b) repp(i, a, b, 1)
#define bck(i, a, b) bckk(i, a, b, 1)
#define mx(x) *max_element(all(x))
#define mn(x) *min_element(all(x))
#define summ(x) accumulate(all(x), 0LL)
#define mem(x, y) memset(x, y, sizeof(x))
#define count_0(x) __builtin_clzll(x)
#define count_1(x) __builtin_popcountll(x)
#define isEven(x) __builtin_parityll(x)
#define mbit(x) __lg(x)
#define cins(x) for (auto &i : x) cin >> i
#define ceils(x, y) (x + y - 1) / y
#define srt(x) is_sorted(all(x))
#define gcd __gcd
#define endl '\n';
class custom_hash {
    public:
    static uint64_t splitmix64(uint64_t x) 
    {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }
    size_t operator()(uint64_t x) const 
    {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};
template <typename T> using max_heap = priority_queue<T>;
template <typename T> using min_heap = priority_queue<T, vector<T>, greater<T>>;
template <typename T> using vec = vector<vector<T>>;
template <typename T> using uset = unordered_set<T, custom_hash>;
template <typename T1, typename T2> void amax(T1 &x, T2 y) {if(x < y) x = y;}
template <typename T1, typename T2> void amin(T1 &x, T2 y) {if(x > y) x = y;}
 
const double pi = acos(-1.0);
const double eps = 1e-9;
const int mod = 1e9 + 7;
const int mod2 = 998244353;
const int inf = 2e18;
const int maxn = 2e5 + 10;
const int maxx = 2e6 + 10;
char dir[] = {'D', 'L', 'R', 'U'};
const int dx[] = {1, 0, 0, -1, 1, 1, -1, -1};
const int dy[] = {0, -1, 1, 0, -1, 1, -1, 1};

void __print(int x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(bool x) {cerr << (x ? "true" : "false");}
void _print() {cerr << "]\n";}
 
template <typename T1, typename T2> void __print(const pair<T1, T2> &x) {cerr << '{'; __print(x.ff); cerr << ','; __print(x.ss); cerr << '}';}
template <typename T> void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
template <typename T1, typename... T2> void _print(T1 t, T2... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}

int power(int a, int y, int m)
{
    int res = 1;
    a = a % m; 
    while (y > 0)
    {
        if (y & 1)
            res = (res * a) % m;
        y = y >> 1LL;
        a = (a * a) % m;
    }
    return res;
}
 
bool isSqr(int x)
{
    int y = sqrtl(x);
    return x == y * y; 
}
 
bool isPrime(int x)
{
    if (x == 1)
        return false;
    for (int i = 2; i * i <= x; i++)
        if (x % i == 0)
            return false;
    return true;
}

int inverse(int n, int m) {return power(n, m - 2, m);}
int mod_add(int a, int b, int m) {a = a % m; b = b % m; return (((a + b) % m) + m) % m;}
int mod_mul(int a, int b, int m) {a = a % m; b = b % m; return (((a * b) % m) + m) % m;}
int mod_sub(int a, int b, int m) {a = a % m; b = b % m; return (((a - b) % m) + m) % m;}
int mod_div(int a, int b, int m) {a = a % m; b = b % m; return (mod_mul(a, inverse(b, m), m));}

void IOS()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    cout.precision(20);
    cout.setf(ios::fixed);
    
}
void solve()
{
    int n;
    cin>>n;
    vector <int> a(n);
    int ans = 0;
    for(auto &x : a){
        cin>>x;
        ans+=x;
    }
    for(auto x:a){
        if(x*n==ans){
            cout<<"YES"<<endl;
            return;
            }
        
    }
    cout<<"NO"<<endl;
}  
main()
{
    IOS();
    int testcases = 1;
    cin >> testcases;
    while (testcases--)
        solve();
    return 0;
}