Codeforces Round 825 (Div. 2)——B

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define endl "\n"
inline int gcd(int a, int b) {
    return b > 0 ? gcd(b, a % b) : a;
}
inline int lcm(int a, int b) {
    return a / gcd(a, b) * b;
}
const int N = 1e5 + 5;
int a[N],b[N];
int main()
{
    ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
    int T = 1;
    cin >> T;
    while (T--) {
        int n, jud = 0;
        cin >> n;
        for (int i = 1; i <= n; i++)cin >> a[i];
        a[0] = a[n + 1] = 1;
        for (int i = 1; i <= n + 1; i++) {
            b[i] = lcm(a[i], a[i-1]);
        }
        for (int i = 1; i <= n; i++) {
            if (a[i] != gcd(b[i], b[i + 1]))jud = 1;
        }
        if (jud)cout << "NO" << endl;
        else cout << "YES" << endl;
    }
}