#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-8;
const int mod = 1e9 + 7;
const int N = 1e6 + 10;
const int inf = 1e9;
int t, n, a[N], b[N];
int gao(int x) {
  int res = b[1] - x;
  for (int i = 2; i <= n; i++) {
    res = b[i] - max(a[i] - res, 0);
    if (res < 0) return -1;
  }
  return res;
}
int main() {
  ios::sync_with_stdio(false);
  cin >> t;
  while (t--) {
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i <= n; i++) cin >> b[i];
    int l = 0, r = b[1], ans = 0;
    while (l <= r) {
      int mid = l + r >> 1;
      int ret = gao(mid);
      if (ret == -1) {
        r = mid - 1;
      } else
        l = mid + 1;
      if (ret != -1 && ret + mid >= a[1]) {
        ans = 1;
      }
    }
    if (ans)
      puts("YES");
    else
      puts("NO");
  }
  return 0;
}
