description: There are n heaps of stone. The i-th heap has h_i stones. You want to change the number of stones in the heap by performing the following process once: 
  
    * You go through the heaps from the 3-rd heap to the n-th heap, in this order. 
    * Let i be the number of the current heap. 
    * You can choose a number d (0 ≤ 3 ⋅ d ≤ h_i), move d stones from the i-th heap to the (i - 1)-th heap, and 2 ⋅ d stones from the i-th heap to the (i - 2)-th heap. 
    * So after that h_i is decreased by 3 ⋅ d, h_{i - 1} is increased by d, and h_{i - 2} is increased by 2 ⋅ d. 
    * You can choose different or same d for different operations. Some heaps may become empty, but they still count as heaps. 
  
  
  
  What is the maximum number of stones in the smallest heap after the process?
  
  Input
  
  Each test contains multiple test cases. The first line contains the number of test cases t (1 ≤ t ≤ 2⋅ 10^5). Description of the test cases follows.
  
  The first line of each test case contains a single integer n (3 ≤ n ≤ 2 ⋅ 10^5).
  
  The second lines of each test case contains n integers h_1, h_2, h_3, …, h_n (1 ≤ h_i ≤ 10^9).
  
  It is guaranteed that the sum of n over all test cases does not exceed 2 ⋅ 10^5.
  
  Output
  
  For each test case, print the maximum number of stones that the smallest heap can contain.
  
  Example
  
  Input
  
  
  4
  4
  1 2 10 100
  4
  100 100 100 1
  5
  5 1 1 1 8
  6
  1 2 3 4 5 6
  
  
  Output
  
  
  7
  1
  1
  3
  
  Note
  
  In the first test case, the initial heap sizes are [1, 2, 10, 100]. We can move the stones as follows. 
  
    * move 3 stones and 6 from the 3-rd heap to the 2-nd and 1 heap respectively. The heap sizes will be [7, 5, 1, 100]; 
    * move 6 stones and 12 stones from the last heap to the 3-rd and 2-nd heap respectively. The heap sizes will be [7, 17, 7, 82]. 
  
  
  
  In the second test case, the last heap is 1, and we can not increase its size.
  
  In the third test case, it is better not to move any stones.
  
  In the last test case, the final achievable configuration of the heaps can be [3, 5, 3, 4, 3, 3].
solution: from __future__ import division, print_function
  
  import os,sys
  from io import BytesIO, IOBase
  
  if sys.version_info[0] < 3:
      from __builtin__ import xrange as range
      from future_builtins import ascii, filter, hex, map, oct, zip
  
  from bisect import bisect_left as lower_bound, bisect_right as upper_bound 
  def so():  return int(input())
  def st():  return input()
  def mj():  return map(int,input().strip().split(" "))
  def msj(): return (map(str,input().strip().split(" ")))
  def le():  return list(map(int,input().split()))
  def rc():  return map(float,input().split())
  def lebe():return list(map(int, input()))
  
  def dmain():
      sys.setrecursionlimit(1000000)
      threading.stack_size(1024000)
      thread = threading.Thread(target=main)
      thread.start()
  def joro(L):
      return(''.join(map(str, L)))
  
  
  def decimalToBinary(n): return bin(n).replace("0b","")
  
  
  def isprime(n):
      for i in range(2,int(n**0.5)+1):
          if n%i==0:
              return False
      return True
  def npr(n, r):
      return factorial(n) // factorial(n - r) if n >= r else 0
   
   
  
      
   
   
  def lower_bound(li, num):
      answer = -1
      start = 0
      end = len(li) - 1
   
      while (start <= end):
          middle = (end + start) // 2
          if li[middle] >= num:
              answer = middle
              end = middle - 1
          else:
              start = middle + 1
      return answer  # min index where x is not less than num
   
   
  def upper_bound(li, num):
      answer = -1
      start = 0
      end = len(li) - 1
   
      while (start <= end):
          middle = (end + start) // 2
   
          if li[middle] <= num:
              answer = middle
              start = middle + 1
   
          else:
              end = middle - 1
      return answer  # max index where x is not greater than num
  def tir(a,b,c):
      if(0==c):
          return 1
      if(len(a)<=b):
          return 0
      
      if(c!=-1):
          return (tir(a,1+b,c+a[b]) or tir(a,b+1,c-a[b]) or tir(a,1+b,c)) 
          
          
      else:
          return (tir(a,1+b,a[b]) or tir(a,b+1,-a[b]) or tir(a,1+b,-1))
  hoi=int(2**20)        
   
  def abs(x):
      return x if x >= 0 else -x
   
   
  def binary_search(li, val, lb, ub):
      # print(lb, ub, li)
      ans = -1
      while (lb <= ub):
          mid = (lb + ub) // 2
          # print('mid is',mid, li[mid])
          if li[mid] > val:
              ub = mid - 1
          elif val > li[mid]:
              lb = mid + 1
          else:
              ans = mid  # return index
              break
      return ans
   
   
  def kadane(x):  # maximum sum contiguous subarray
      sum_so_far = 0
      current_sum = 0
      for i in x:
          current_sum += i
          if current_sum < 0:
              current_sum = 0
          else:
              sum_so_far = max(sum_so_far, current_sum)
      return sum_so_far
  
                      
  def pref(li):
      pref_sum = [0]
      for i in li:
          pref_sum.append(pref_sum[-1] + i)
      return pref_sum
   
  
          
          
  def SieveOfEratosthenes(n):
      prime = [True for i in range(n + 1)]
      p = 2
      li = []
      while (p * p <= n):
          if (prime[p] == True):
              for i in range(p * p, n + 1, p):
                  prime[i] = False
          p += 1
   
      for p in range(2, len(prime)):
          if prime[p]:
              li.append(p)
      return li
   
   
  def primefactors(n):
      factors = []
      while (n % 2 == 0):
          factors.append(2)
          n //= 2
      for i in range(3, int(sqrt(n)) + 1, 2):  # only odd factors left
          while n % i == 0:
              factors.append(i)
              n //= i
      if n > 2:  # incase of prime
          factors.append(n)
      return factors
           
      
  def read():
      sys.stdin  = open('input.txt', 'r')  
      sys.stdout = open('output.txt', 'w') 
  def tr(n):
      return n*(n+1)//2
  boi=int(1e9-7)
  doi=int(1e9+7)
  def hup(x, y):
      "Calculate (x ** y) % z efficiently."
      number = 1
      while y:
          if y & 1:
              number = number * x % op
          y >>= 1
          x = x * x % op
      return number
  
  y="YES"
  n="NO"
  def ch(x,L,m):
      M=[]
      for i in L:
          M.append(i)
      for i in range(m-1,1,-1):
          b=M[i]
          if(M[i]<x):
              return 0
          b-=x
          b=min(b,L[i])
          b=b//3
          M[i]-=3*b
          M[i-1]+=b
          M[i-2]+=2*b
      if(M[0]>=x and M[1]>=x):
          return 1
      
  
  
  
      
  def iu():
      import sys
      import math as my
      input=sys.stdin.readline
      m=so()
      L=le()
      lo=-1
      hi=int(1e9)
      while(lo+1<hi):
          jp=(lo+hi)//2
          if(ch(jp,L,m)):
              lo=jp
          else:
              hi=jp
      print(lo)
      
      
      
              
  def main():
      for i in range(so()):
          iu()
          
      
      
      
      
      
      
      
      
      
      
  
      
  
      
          
          
              
      
      
                  
              
                  
                  
                  
                  
              
      
              
              
      
      
      
      
          
              
      
             
              
              
          
      
          
      
      
          
          
          
  
              
                      
                  
                      
                      
                      
                      
                      
                      
          
                  
          
          
         
      
             
            
            
                  
              
          
                  
      
          
          
          
         
              
                  
          
  
  
  
  
  # region fastio
  # template taken from https://github.com/cheran-senthil/PyRival/blob/master/templates/template.py
  
  BUFSIZE = 8192
  
  
  class FastIO(IOBase):
      newlines = 0
  
      def __init__(self, file):
          self._fd = file.fileno()
          self.buffer = BytesIO()
          self.writable = "x" in file.mode or "r" not in file.mode
          self.write = self.buffer.write if self.writable else None
  
      def read(self):
          while True:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
              if not b:
                  break
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines = 0
          return self.buffer.read()
  
      def readline(self):
          while self.newlines == 0:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
              self.newlines = b.count(b"\n") + (not b)
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines -= 1
          return self.buffer.readline()
  
      def flush(self):
          if self.writable:
              os.write(self._fd, self.buffer.getvalue())
              self.buffer.truncate(0), self.buffer.seek(0)
  
  
  class IOWrapper(IOBase):
      def __init__(self, file):
          self.buffer = FastIO(file)
          self.flush = self.buffer.flush
          self.writable = self.buffer.writable
          self.write = lambda s: self.buffer.write(s.encode("ascii"))
          self.read = lambda: self.buffer.read().decode("ascii")
          self.readline = lambda: self.buffer.readline().decode("ascii")
  
  
  def print(*args, **kwargs):
      """Prints the values to a stream, or to sys.stdout by default."""
      sep, file = kwargs.pop("sep", " "), kwargs.pop("file", sys.stdout)
      at_start = True
      for x in args:
          if not at_start:
              file.write(sep)
          file.write(str(x))
          at_start = False
      file.write(kwargs.pop("end", "\n"))
      if kwargs.pop("flush", False):
          file.flush()
  
  
  if sys.version_info[0] < 3:
      sys.stdin, sys.stdout = FastIO(sys.stdin), FastIO(sys.stdout)
  else:
      sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
  
  input = lambda: sys.stdin.readline().rstrip("\r\n")
  
  # endregion
  
  
  if __name__ == "__main__":
      #read()
      main()
      #dmain()
  
  # Comment Read()