#include <bits/stdc++.h>
using namespace std;
const long long MOD = (long long)1e9 + 7;
int t, n, a[1000009], b[1000009];
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> t;
  while (t--) {
    cin >> n;
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < n; i++) cin >> b[i];
    int tmp = min(b[0], a[1]), res = max(0, b[0] - a[1]);
    int nd = max(0, a[1] - b[0]);
    int cur = 0;
    bool ok = true;
    for (int i = 1; i < n - 1; i++) {
      cur = b[i] - nd;
      if (cur < 0) {
        ok = false;
        break;
      }
      if (cur > a[i + 1]) {
        int ttmp = min(tmp, cur - a[i + 1]);
        tmp -= ttmp;
        res += ttmp;
      }
      tmp = min(tmp, min(cur, a[i + 1]));
      nd = max(0, a[i + 1] - cur);
    }
    cur = b[n - 1] - nd;
    if (cur < 0)
      ok = false;
    else if (res + cur < a[0])
      ok = false;
    if (ok)
      cout << "YES\n";
    else
      cout << "NO\n";
  }
  return 0;
}
