t=int(input())

def ilist():
      return list(map(int,input().split()))

for line in range(t):
      m=int(input())
      a=ilist()
      b=ilist()
      ans=0
      for i in range(1,m):
          tmp=min(a[i],b[m-i])
          a[i]-=tmp
          b[m-i]-=tmp
          ans+=tmp
      if ans:
          ans+=a[m-1]+b[m-1]
          for i in range(m-1):
              ans+=min(a[i],b[m-1-i])    
      print(ans)