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: # ---------------------------iye ha aam zindegi---------------------------------------------
  import math
  import random
  import heapq,bisect
  import sys
  from collections import deque, defaultdict
  from fractions import Fraction
  import sys
  from itertools import permutations
  from collections import defaultdict
  mod = 10 ** 9 + 7
  mod1 = 998244353
  
  # ------------------------------warmup----------------------------
  import os
  import sys
  from io import BytesIO, IOBase
  
  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")
  
  
  sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
  input = lambda: sys.stdin.readline().rstrip("\r\n")
  
  #----------------------------------------------iye ha aam zindegi-----------------------------------
  
  class SegmentTree:
      def __init__(self, data, default=(-2,-2), func=lambda a, b: max(a,b)):
          """initialize the segment tree with data"""
          self._default = default
          self._func = func
          self._len = len(data)
          self._size = _size = 1 << (self._len - 1).bit_length()
  
          self.data = [default] * (2 * _size)
          self.data[_size:_size + self._len] = data
          for i in reversed(range(_size)):
              self.data[i] = func(self.data[i + i], self.data[i + i + 1])
  
      def __delitem__(self, idx):
          self[idx] = self._default
  
      def __getitem__(self, idx):
          return self.data[idx + self._size]
  
      def __setitem__(self, idx, value):
          idx += self._size
          self.data[idx] = value
          idx >>= 1
          while idx:
              self.data[idx] = self._func(self.data[2 * idx], self.data[2 * idx + 1])
              idx >>= 1
  
      def __len__(self):
          return self._len
  
      def query(self, start, stop):
          if start == stop:
              return self.__getitem__(start)
          stop += 1
          start += self._size
          stop += self._size
  
          res = self._default
          while start < stop:
              if start & 1:
                  res = self._func(res, self.data[start])
                  start += 1
              if stop & 1:
                  stop -= 1
                  res = self._func(res, self.data[stop])
              start >>= 1
              stop >>= 1
          return res
  
      def __repr__(self):
          return "SegmentTree({0})".format(self.data)
  
  
  # -------------------------------iye ha chutiya zindegi-------------------------------------
  class SortedList:
      def __init__(self, iterable=[], _load=200):
          """Initialize sorted list instance."""
          values = sorted(iterable)
          self._len = _len = len(values)
          self._load = _load
          self._lists = _lists = [values[i:i + _load] for i in range(0, _len, _load)]
          self._list_lens = [len(_list) for _list in _lists]
          self._mins = [_list[0] for _list in _lists]
          self._fen_tree = []
          self._rebuild = True
  
      def _fen_build(self):
          """Build a fenwick tree instance."""
          self._fen_tree[:] = self._list_lens
          _fen_tree = self._fen_tree
          for i in range(len(_fen_tree)):
              if i | i + 1 < len(_fen_tree):
                  _fen_tree[i | i + 1] += _fen_tree[i]
          self._rebuild = False
  
      def _fen_update(self, index, value):
          """Update `fen_tree[index] += value`."""
          if not self._rebuild:
              _fen_tree = self._fen_tree
              while index < len(_fen_tree):
                  _fen_tree[index] += value
                  index |= index + 1
  
      def _fen_query(self, end):
          """Return `sum(_fen_tree[:end])`."""
          if self._rebuild:
              self._fen_build()
  
          _fen_tree = self._fen_tree
          x = 0
          while end:
              x += _fen_tree[end - 1]
              end &= end - 1
          return x
  
      def _fen_findkth(self, k):
          """Return a pair of (the largest `idx` such that `sum(_fen_tree[:idx]) <= k`, `k - sum(_fen_tree[:idx])`)."""
          _list_lens = self._list_lens
          if k < _list_lens[0]:
              return 0, k
          if k >= self._len - _list_lens[-1]:
              return len(_list_lens) - 1, k + _list_lens[-1] - self._len
          if self._rebuild:
              self._fen_build()
  
          _fen_tree = self._fen_tree
          idx = -1
          for d in reversed(range(len(_fen_tree).bit_length())):
              right_idx = idx + (1 << d)
              if right_idx < len(_fen_tree) and k >= _fen_tree[right_idx]:
                  idx = right_idx
                  k -= _fen_tree[idx]
          return idx + 1, k
  
      def _delete(self, pos, idx):
          """Delete value at the given `(pos, idx)`."""
          _lists = self._lists
          _mins = self._mins
          _list_lens = self._list_lens
  
          self._len -= 1
          self._fen_update(pos, -1)
          del _lists[pos][idx]
          _list_lens[pos] -= 1
  
          if _list_lens[pos]:
              _mins[pos] = _lists[pos][0]
          else:
              del _lists[pos]
              del _list_lens[pos]
              del _mins[pos]
              self._rebuild = True
  
      def _loc_left(self, value):
          """Return an index pair that corresponds to the first position of `value` in the sorted list."""
          if not self._len:
              return 0, 0
  
          _lists = self._lists
          _mins = self._mins
  
          lo, pos = -1, len(_lists) - 1
          while lo + 1 < pos:
              mi = (lo + pos) >> 1
              if value <= _mins[mi]:
                  pos = mi
              else:
                  lo = mi
  
          if pos and value <= _lists[pos - 1][-1]:
              pos -= 1
  
          _list = _lists[pos]
          lo, idx = -1, len(_list)
          while lo + 1 < idx:
              mi = (lo + idx) >> 1
              if value <= _list[mi]:
                  idx = mi
              else:
                  lo = mi
  
          return pos, idx
  
      def _loc_right(self, value):
          """Return an index pair that corresponds to the last position of `value` in the sorted list."""
          if not self._len:
              return 0, 0
  
          _lists = self._lists
          _mins = self._mins
  
          pos, hi = 0, len(_lists)
          while pos + 1 < hi:
              mi = (pos + hi) >> 1
              if value < _mins[mi]:
                  hi = mi
              else:
                  pos = mi
  
          _list = _lists[pos]
          lo, idx = -1, len(_list)
          while lo + 1 < idx:
              mi = (lo + idx) >> 1
              if value < _list[mi]:
                  idx = mi
              else:
                  lo = mi
  
          return pos, idx
  
      def add(self, value):
          """Add `value` to sorted list."""
          _load = self._load
          _lists = self._lists
          _mins = self._mins
          _list_lens = self._list_lens
  
          self._len += 1
          if _lists:
              pos, idx = self._loc_right(value)
              self._fen_update(pos, 1)
              _list = _lists[pos]
              _list.insert(idx, value)
              _list_lens[pos] += 1
              _mins[pos] = _list[0]
              if _load + _load < len(_list):
                  _lists.insert(pos + 1, _list[_load:])
                  _list_lens.insert(pos + 1, len(_list) - _load)
                  _mins.insert(pos + 1, _list[_load])
                  _list_lens[pos] = _load
                  del _list[_load:]
                  self._rebuild = True
          else:
              _lists.append([value])
              _mins.append(value)
              _list_lens.append(1)
              self._rebuild = True
  
      def discard(self, value):
          """Remove `value` from sorted list if it is a member."""
          _lists = self._lists
          if _lists:
              pos, idx = self._loc_right(value)
              if idx and _lists[pos][idx - 1] == value:
                  self._delete(pos, idx - 1)
  
      def remove(self, value):
          """Remove `value` from sorted list; `value` must be a member."""
          _len = self._len
          self.discard(value)
          if _len == self._len:
              raise ValueError('{0!r} not in list'.format(value))
  
      def pop(self, index=-1):
          """Remove and return value at `index` in sorted list."""
          pos, idx = self._fen_findkth(self._len + index if index < 0 else index)
          value = self._lists[pos][idx]
          self._delete(pos, idx)
          return value
  
      def bisect_left(self, value):
          """Return the first index to insert `value` in the sorted list."""
          pos, idx = self._loc_left(value)
          return self._fen_query(pos) + idx
  
      def bisect_right(self, value):
          """Return the last index to insert `value` in the sorted list."""
          pos, idx = self._loc_right(value)
          return self._fen_query(pos) + idx
  
      def count(self, value):
          """Return number of occurrences of `value` in the sorted list."""
          return self.bisect_right(value) - self.bisect_left(value)
  
      def __len__(self):
          """Return the size of the sorted list."""
          return self._len
  
      def __getitem__(self, index):
          """Lookup value at `index` in sorted list."""
          pos, idx = self._fen_findkth(self._len + index if index < 0 else index)
          return self._lists[pos][idx]
  
      def __delitem__(self, index):
          """Remove value at `index` from sorted list."""
          pos, idx = self._fen_findkth(self._len + index if index < 0 else index)
          self._delete(pos, idx)
  
      def __contains__(self, value):
          """Return true if `value` is an element of the sorted list."""
          _lists = self._lists
          if _lists:
              pos, idx = self._loc_left(value)
              return idx < len(_lists[pos]) and _lists[pos][idx] == value
          return False
  
      def __iter__(self):
          """Return an iterator over the sorted list."""
          return (value for _list in self._lists for value in _list)
  
      def __reversed__(self):
          """Return a reverse iterator over the sorted list."""
          return (value for _list in reversed(self._lists) for value in reversed(_list))
  
      def __repr__(self):
          """Return string representation of sorted list."""
          return 'SortedList({0})'.format(list(self))
  #-----------------------------sortedlist--------------------------------------------------------------
  class Factorial:
      def __init__(self, MOD):
          self.MOD = MOD
          self.factorials = [1, 1]
          self.invModulos = [0, 1]
          self.invFactorial_ = [1, 1]
  
      def calc(self, n):
          if n <= -1:
              print("Invalid argument to calculate n!")
              print("n must be non-negative value. But the argument was " + str(n))
              exit()
          if n < len(self.factorials):
              return self.factorials[n]
          nextArr = [0] * (n + 1 - len(self.factorials))
          initialI = len(self.factorials)
          prev = self.factorials[-1]
          m = self.MOD
          for i in range(initialI, n + 1):
              prev = nextArr[i - initialI] = prev * i % m
          self.factorials += nextArr
          return self.factorials[n]
  
      def inv(self, n):
          if n <= -1:
              print("Invalid argument to calculate n^(-1)")
              print("n must be non-negative value. But the argument was " + str(n))
              exit()
          p = self.MOD
          pi = n % p
          if pi < len(self.invModulos):
              return self.invModulos[pi]
          nextArr = [0] * (n + 1 - len(self.invModulos))
          initialI = len(self.invModulos)
          for i in range(initialI, min(p, n + 1)):
              next = -self.invModulos[p % i] * (p // i) % p
              self.invModulos.append(next)
          return self.invModulos[pi]
  
      def invFactorial(self, n):
          if n <= -1:
              print("Invalid argument to calculate (n^(-1))!")
              print("n must be non-negative value. But the argument was " + str(n))
              exit()
          if n < len(self.invFactorial_):
              return self.invFactorial_[n]
          self.inv(n)  # To make sure already calculated n^-1
          nextArr = [0] * (n + 1 - len(self.invFactorial_))
          initialI = len(self.invFactorial_)
          prev = self.invFactorial_[-1]
          p = self.MOD
          for i in range(initialI, n + 1):
              prev = nextArr[i - initialI] = (prev * self.invModulos[i % p]) % p
          self.invFactorial_ += nextArr
          return self.invFactorial_[n]
  
  
  class Combination:
      def __init__(self, MOD):
          self.MOD = MOD
          self.factorial = Factorial(MOD)
  
      def ncr(self, n, k):
          if k < 0 or n < k:
              return 0
          k = min(k, n - k)
          f = self.factorial
          return f.calc(n) * f.invFactorial(max(n - k, k)) * f.invFactorial(min(k, n - k)) % self.MOD
  
  
  # --------------------------------------iye ha combinations ka zindegi---------------------------------
  def powm(a, n, m):
      if a == 1 or n == 0:
          return 1
      if n % 2 == 0:
          s = powm(a, n // 2, m)
          return s * s % m
      else:
          return a * powm(a, n - 1, m) % m
  
  
  # --------------------------------------iye ha power ka zindegi---------------------------------
  def sort_list(list1, list2):
      zipped_pairs = zip(list2, list1)
  
      z = [x for _, x in sorted(zipped_pairs)]
  
      return z
  
  
  # --------------------------------------------------product----------------------------------------
  def product(l):
      por = 1
      for i in range(len(l)):
          por *= l[i]
      return por
  
  
  # --------------------------------------------------binary----------------------------------------
  def binarySearchCount(arr, n, key):
      left = 0
      right = n - 1
  
      count = 0
  
      while (left <= right):
          mid = int((right + left) / 2)
  
          # Check if middle element is
          # less than or equal to key
          if (arr[mid] <= key):
              count = mid + 1
              left = mid + 1
  
          # If key is smaller, ignore right half
          else:
              right = mid - 1
  
      return count
  
  
  # --------------------------------------------------binary----------------------------------------
  def countdig(n):
      c = 0
      while (n > 0):
          n //= 10
          c += 1
      return c
  def binary(x, length):
      y = bin(x)[2:]
      return y if len(y) >= length else "0" * (length - len(y)) + y
  
  def countGreater(arr, n, k):
      l = 0
      r = n - 1
  
      # Stores the index of the left most element
      # from the array which is greater than k
      leftGreater = n
  
      # Finds number of elements greater than k
      while (l <= r):
          m = int(l + (r - l) / 2)
          if (arr[m] >= k):
              leftGreater = m
              r = m - 1
  
          # If mid element is less than
          # or equal to k update l
          else:
              l = m + 1
  
      # Return the count of elements
      # greater than k
      return (n - leftGreater)
  #-----------------------------------------------trie-----------------------------------------------
  class TrieNode:
      def __init__(self):
          self.children = [None] * 26
          self.isEndOfWord = False
  class Trie:
      def __init__(self):
          self.root = self.getNode()
      def getNode(self):
          return TrieNode()
      def _charToIndex(self, ch):
          return ord(ch) - ord('a')
      def insert(self, key):
          pCrawl = self.root
          length = len(key)
          for level in range(length):
              index = self._charToIndex(key[level])
              if not pCrawl.children[index]:
                  pCrawl.children[index] = self.getNode()
              pCrawl = pCrawl.children[index]
          pCrawl.isEndOfWord = True
      def search(self, key):
          pCrawl = self.root
          length = len(key)
          for level in range(length):
              index = self._charToIndex(key[level])
              if not pCrawl.children[index]:
                  return False
              pCrawl = pCrawl.children[index]
          return pCrawl != None and pCrawl.isEndOfWord
  #-----------------------------------------trie---------------------------------
  class Node:
      def __init__(self, data):
          self.data = data
          self.count=0
          self.left = None  # left node for 0
          self.right = None  # right node for 1
  class BinaryTrie:
      def __init__(self):
          self.root = Node(0)
      def insert(self, pre_xor):
          self.temp = self.root
          for i in range(31, -1, -1):
              val = pre_xor & (1 << i)
              if val:
                  if not self.temp.right:
                      self.temp.right = Node(0)
                  self.temp = self.temp.right
                  self.temp.count+=1
              if not val:
                  if not self.temp.left:
                      self.temp.left = Node(0)
                  self.temp = self.temp.left
                  self.temp.count += 1
          self.temp.data = pre_xor
      def query(self, xor):
          self.temp = self.root
          for i in range(31, -1, -1):
              val = xor & (1 << i)
              if not val:
                  if self.temp.left and self.temp.left.count>0:
                      self.temp = self.temp.left
                  elif self.temp.right:
                      self.temp = self.temp.right
              else:
                  if self.temp.right and self.temp.right.count>0:
                      self.temp = self.temp.right
                  elif self.temp.left:
                      self.temp = self.temp.left
              self.temp.count-=1
          return xor ^ self.temp.data
  # --------------------------------------------------binary-----------------------------------
  for ik in range(int(input())):
      n=int(input())
      e=list(map(int,input().split()))
      def find(x):
          l=e+[]
          for i in range(n-1,1,-1):
              if l[i]<x:
                  return False
              else:
                  d=min((l[i]-x)//3,e[i]//3)
                  l[i]-=3*d
                  l[i-1]+=d
                  l[i-2]+=2*d
          if l[0]>=x and l[1]>=x:
              return True
          return False
      st=0
      end=max(e)
      ans=0
      while(st<=end):
          mid=(st+end)//2
          if find(mid)==True:
              ans=mid
              st=mid+1
          else:
              end=mid-1
      print(ans)