code2143A.cpp

/*
 * Contest : Codeforces
 * Problem : 2143A - All Lengths Subtraction
 * Link    : https://codeforces.com/contest/2143/problem/A
 */

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#define fastio ios::sync_with_stdio(0); cin.tie(0);

bool solve() {
  ll n; cin >> n;
  vector<ll> v(n);
  for (auto &i : v) {
    cin >> i;
    if (i == n) i--;
  }

  ll k = 2;
  while (k <= n) {
    ll cnt = 1, last = 0;
    for (int i = 0; i < n - 1; ++i) {
      if (v[i] == v[i + 1] && v[i] == n - k + 1) {
        v[i]--;
        cnt++;
        last = i + 1;
      }
    }
    v[last]--;

    if (cnt != k) return false;
    k++;
  }
  return true;
}

int main() {
  fastio

  ll t; cin >> t;
  while (t--) cout << (solve() ? "YES" : "NO") << '\n';

  return 0;
}