#include <bits/stdc++.h>
using namespace std;
const long long MOD = (long long)1e9 + 7;
const long double PI = 3.141592653589793238462643383279502884197;
long long fac[1] = {1}, inv[1] = {1};
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
long long mp(long long a, long long b) {
  long long ret = 1;
  while (b) {
    if (b & 1) ret = ret * a % MOD;
    a = a * a % MOD;
    b >>= 1;
  }
  return ret;
}
long long cmb(long long r, long long c) {
  return fac[r] * inv[c] % MOD * inv[r - c] % MOD;
}
priority_queue<int, vector<int>, greater<int>> pq;
int n;
int a[1000000], b[1000000], tmp[1000000];
int main() {
  int tc;
  scanf("%d", &tc);
  while (tc--) {
    scanf("%d", &n);
    for (int i = 0; i < n; i++) scanf("%d", &b[i]);
    for (int i = 0; i < n; i++) scanf("%d", &a[i]);
    int l = 0, r = a[0], mid;
    while (l <= r) {
      mid = (l + r) / 2;
      int p = mid, k, flag = 0;
      for (int i = 1; i < n; i++) {
        k = p + a[i] - b[i];
        if (k < 0) {
          flag = 1;
          break;
        }
        p = min(k, a[i]);
      }
      if (flag)
        l = mid + 1;
      else
        r = mid - 1;
    }
    int p = l, k, flag = 0;
    if (p > a[0]) {
      printf("NO\n");
      continue;
    }
    for (int i = 1; i < n; i++) {
      k = p + a[i] - b[i];
      if (k < 0) {
        flag = 1;
        break;
      }
      p = min(k, a[i]);
    }
    if (p + (a[0] - l) >= b[0] && !flag)
      printf("YES\n");
    else
      printf("NO\n");
  }
}
