#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
template <typename T>
int sz(const T &a) {
  return (int)a.size();
}
const int MAXN = 1e6 + 1;
ll cost[MAXN];
ll cap[MAXN];
ll te[MAXN], te2[MAXN];
int n;
int check(ll am) {
  if (am > min(cost[0], cap[n - 1])) return 0;
  for (int i = 0; i < n; i++) {
    te[i] = cost[i], te2[i] = cap[i];
  }
  te[0] -= am;
  te2[n - 1] -= am;
  int ret = 0;
  for (int i = 0; i < n; i++) {
    te2[i] -= te[i];
    if (te2[i] < 0) return ret;
    if (i < n - 1) {
      ll x = min(te[i + 1], te2[i]);
      te[i + 1] -= x, te2[i] -= x;
      if (te2[i]) ret = -1;
    }
  }
  return 1;
}
int main() {
  cin.tie(NULL);
  ios_base::sync_with_stdio(false);
  int t;
  cin >> t;
  while (t--) {
    cin >> n;
    for (int i = 0; i < n; i++) {
      cin >> cost[i];
    }
    for (int i = 0; i < n; i++) {
      cin >> cap[i];
    }
    ll lo = 0, hi = min(cost[0], cap[n - 1]);
    bool done = false;
    while (lo != hi) {
      ll mid = (lo + hi) / 2 + 1;
      int te = check(mid);
      if (te == 1) {
        printf("YES\n");
        done = true;
        break;
      } else if (te == -1)
        hi = mid - 1;
      else
        lo = mid;
    }
    if (!done) {
      if (check(lo) == 1 || check(lo + 1) == 1) {
        printf("YES\n");
        done = true;
      }
    }
    if (!done) {
      printf("NO\n");
    }
  }
  return 0;
}
