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: import array
  import bisect
  import heapq
  import math
  import collections
  import sys
  import copy
  from functools import reduce
  import decimal
  from io import BytesIO, IOBase
  import os
  import itertools
  import functools
  from types import GeneratorType
  
  #
  # sys.setrecursionlimit(10 ** 9)
  decimal.getcontext().rounding = decimal.ROUND_HALF_UP
  
  graphDict = collections.defaultdict
  
  queue = collections.deque
  
  
  ################## pypy deep recursion handling ##############
  # Author = @pajenegod
  def bootstrap(f, stack=[]):
      def wrappedfunc(*args, **kwargs):
          to = f(*args, **kwargs)
          if stack:
              return to
          else:
              while True:
                  if type(to) is GeneratorType:
                      stack.append(to)
                      to = next(to)
                  else:
                      stack.pop()
                      if not stack:
                          return to
                      to = stack[-1].send(to)
  
      return wrappedfunc
  
  
  ################## Graphs ###################
  class Graphs:
      def __init__(self):
          self.graph = graphDict(set)
  
      def add_edge(self, u, v):
          self.graph[u].add(v)
          self.graph[v].add(u)
  
      def dfs_utility(self, nodes, visited_nodes, colors, parity, level):
          global count
          if nodes == 1:
              colors[nodes] = -1
          else:
              if len(self.graph[nodes]) == 1 and parity % 2 == 0:
                  if q == 1:
                      colors[nodes] = 1
                  else:
                      colors[nodes] = -1
                      count += 1
              else:
                  if parity % 2 == 0:
                      colors[nodes] = -1
                  else:
                      colors[nodes] = 1
          visited_nodes.add(nodes)
          for neighbour in self.graph[nodes]:
              new_level = level + 1
              if neighbour not in visited_nodes:
                  self.dfs_utility(neighbour, visited_nodes, colors, level - 1, new_level)
  
      def dfs(self, node):
          Visited = set()
          color = collections.defaultdict()
          self.dfs_utility(node, Visited, color, 0, 0)
          return color
  
      def bfs(self, node, f_node):
          count = float("inf")
          visited = set()
          level = 0
          if node not in visited:
              queue.append([node, level])
              visited.add(node)
          flag = 0
          while queue:
              parent = queue.popleft()
              if parent[0] == f_node:
                  flag = 1
                  count = min(count, parent[1])
              level = parent[1] + 1
              for item in self.graph[parent[0]]:
                  if item not in visited:
                      queue.append([item, level])
                      visited.add(item)
          return count if flag else -1
          return False
  
  
  ################### Tree Implementaion ##############
  class Tree:
      def __init__(self, data):
          self.data = data
          self.left = None
          self.right = None
  
  
  def inorder(node, lis):
      if node:
          inorder(node.left, lis)
          lis.append(node.data)
          inorder(node.right, lis)
      return lis
  
  
  def leaf_node_sum(root):
      if root is None:
          return 0
      if root.left is None and root.right is None:
          return root.data
      return leaf_node_sum(root.left) + leaf_node_sum(root.right)
  
  
  def hight(root):
      if root is None:
          return -1
      if root.left is None and root.right is None:
          return 0
      return max(hight(root.left), hight(root.right)) + 1
  
  
  ################## Union Find #######################
  class UnionFind():
      parents = []
      sizes = []
      count = 0
  
      def __init__(self, n):
          self.count = n
          self.parents = [i for i in range(n)]
          self.sizes = [1 for i in range(n)]
  
      def find(self, i):
          if self.parents[i] == i:
              return i
          else:
              self.parents[i] = self.find(self.parents[i])
              return self.parents[i]
  
      def unite(self, i, j):
          root_i = self.find(i)
          root_j = self.find(j)
          if root_i == root_j:
              return
          elif root_i < root_j:
              self.parents[root_j] = root_i
              self.sizes[root_i] += self.sizes[root_j]
          else:
              self.parents[root_i] = root_j
              self.sizes[root_j] += self.sizes[root_i]
  
      def same(self, i, j):
          return self.find(i) == self.find(j)
  
      def size(self, i):
          return self.sizes[self.find(i)]
  
      def group_count(self):
          return len(set(self.find(i) for i in range(self.count)))
  
      def answer(self, extra, p, q):
          dic = collections.Counter()
          for q in range(n):
              dic[self.find(q)] = self.size(q)
          hq = list(dic.values())
          heapq._heapify_max(hq)
          ans = -1
          for z in range(extra + 1):
              if hq:
                  ans += heapq._heappop_max(hq)
              else:
                  break
          return ans
  
  
  #################################################
  
  def rounding(n):
      return int(decimal.Decimal(f'{n}').to_integral_value())
  
  
  def factors(n):
      return set(reduce(list.__add__,
                        ([i, n // i] for i in range(1, int(n ** 0.5) + 1) if n % i == 0)))
  
  
  def p_sum(array):
      return list(itertools.accumulate(array))
  
  
  def base_change(nn, bb):
      if nn == 0:
          return [0]
      digits = []
      while nn:
          digits.append(int(nn % bb))
          nn //= bb
      return digits[::-1]
  
  
  def diophantine(a: int, b: int, c: int):
      d, x, y = extended_gcd(a, b)
      r = c // d
      return r * x, r * y
  
  
  @bootstrap
  def extended_gcd(a: int, b: int):
      if b == 0:
          d, x, y = a, 1, 0
      else:
          (d, p, q) = yield extended_gcd(b, a % b)
          x = q
          y = p - q * (a // b)
  
      yield d, x, y
  
  
  ######################################################################################
  
  '''
  Knowledge and awareness are vague, and perhaps better called illusions.
  Everyone lives within their own subjective interpretation.
                                                              ~Uchiha Itachi
  '''
  
  ################################ <fast I/O> ###########################################
  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, **kwargs):
          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")
  
  
  sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
  
  
  #############################################<I/O Region >##############################################
  
  
  def inp():
      return sys.stdin.readline().strip()
  
  
  def map_inp(v_type):
      return map(v_type, inp().split())
  
  
  def list_inp(v_type):
      return list(map_inp(v_type))
  
  
  def interactive():
      return sys.stdout.flush()
  
  
  ######################################## Solution ####################################
  
  def valid(x):
      temp = list.copy(arr)
      flag = 1
      for i in range(n - 2):
          if flag:
              if arr[i] < x:
                  return False
              div, rem = divmod(arr[i] - x, 3)
              temp[i] = x + rem
              temp[i + 1] += div
              temp[i + 2] += 2 * div
              flag = 0
          else:
              if temp[i] < x:
                  return False
              div, rem = divmod(arr[i], 3)
              if temp[i] - (arr[i] - rem) >= x:
                  temp[i] -= (arr[i] - rem)
                  temp[i + 1] += div
                  temp[i + 2] += 2 * div
              else:
                  f = 0
                  l = arr[i]+1
                  while f + 1 < l:
                      m = (f + l) // 2
                      q, r = divmod(m, 3)
                      if temp[i] - (m - r) >= x:
                          f = m
                      else:
                          l = m
                  temp[i] -= (f - f % 3)
                  temp[i + 1] += f // 3
                  temp[i + 2] += 2 * (f // 3)
  
      if min(temp) >= x:
          return True
      else:
          return False
  
  
  for _ in range(int(inp())):
      n = int(inp())
      arr = list_inp(int)
      arr.reverse()
      start = 1
      end = 10 ** 9
      while start + 1 < end:
          mid = (start + end) // 2
          if valid(mid):
              start = mid
          else:
              end = mid
      print(start)
  