#include <bits/stdc++.h>
using namespace std;
using namespace std::chrono;
template <typename A, typename B>
string to_string(pair<A, B> p);
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);
string to_string(const string& s) { return '"' + s + '"'; }
string to_string(const char* s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }
string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}
template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto& x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}
void debug_out() { cout << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cout << " " << to_string(H);
  debug_out(T...);
}
template <typename T>
using mxpq = priority_queue<T>;
template <typename T>
using mnpq = priority_queue<T, vector<T>, greater<T>>;
const long long mod = 998244353;
const long long N = 1e6 + 6;
const long long maxN = 3e4 + 15;
const long long MAX_SIZE = 2e6 + 6;
const long long INF = 0x3f3f3f3f3f3f3f3fll;
const double PI = 3.14159265359;
int dx[4] = {-1, 0, 1, 0};
int dy[4] = {0, 1, 0, -1};
long long powerM(long long x, long long y, long long M = mod) {
  long long v = 1;
  x = x % M;
  while (y > 0) {
    if (y & 1) v = (v * x) % M;
    y = y >> 1;
    x = (x * x) % M;
  }
  return v;
}
long long power(long long x, long long y) {
  long long v = 1;
  while (y > 0) {
    if (y & 1) v = v * x;
    y = y >> 1;
    x = x * x;
  }
  return v;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int testcases = 1;
  cin >> testcases;
  for (int caseno = 1; caseno <= testcases; ++caseno) {
    long long n;
    cin >> n;
    long long a[n];
    for (long long i = 0; i < n; i++) {
      cin >> a[i];
    }
    int flg = 1;
    long long mini = a[0];
    long long left = 0;
    for (int i = 1; i < n; ++i) {
      if (a[i] < left) {
        flg = 0;
        break;
      }
      a[i] -= left;
      if (a[i] > mini) {
        left += (a[i] - mini);
      } else {
        mini = a[i];
      }
    }
    if (flg)
      cout << "YES\n";
    else
      cout << "NO\n";
  }
  return 0;
}
