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 java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.PrintWriter;
  import java.math.BigInteger;
  import java.util.*;
  
  /**
   * @author Mubtasim Shahriar
   */
  
  public class BalancedStoneHeaps {
  
      public static void main(String[] args) {
  
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader sc = new InputReader(inputStream);
          PrintWriter out = new PrintWriter(outputStream);
          Solver solver = new Solver();
          int t = sc.nextInt();
  //        int t = 1;
          while (t-- != 0) {
              solver.solve(sc, out);
          }
          out.close();
  
      }
  
      static class Solver {
          public void solve(InputReader sc, PrintWriter out) {
              int n = sc.nextInt();
              int[] arr = sc.nextIntArray(n);
              int max = 0;
              long sum = 0;
              for(int l : arr) {
                  max = Math.max(max,l);
                  sum += l;
              }
              int l = 1;
              int r = (int)(sum/n);
              long ans = 1;
              while(l<=r) {
                  int[] extra = new int[2];
                  int mid = (l+r)/2;
                  boolean pos = true;
                  for(int i = n-1; i >= 2; i--) {
                      int nowVal = arr[i];
                      int nowExtra = extra[0];
                      int needMore = mid-nowExtra;
                      int canD = 0;
                      if(needMore<=0) {
                          canD = nowVal/3;
                      } else if(needMore<=nowVal) {
                          canD = (nowVal-needMore)/3;
                      }
                      int rest = nowExtra + nowVal - canD * 3;
                      if(rest<mid) {
                          pos = false;
                          break;
                      }
                      extra[0] = extra[1];
                      extra[0] += canD;
                      extra[1] = canD*2;
                  }
                  if(pos) {
                      if(arr[0]+extra[1]<mid || arr[1]+extra[0]<mid) pos = false;
                  }
                  if(pos) {
                      ans = mid;
                      l = mid+1;
                  } else {
                      r = mid-1;
                  }
              }
              out.println(ans);
          }
      }
  
      static void sort(int[] arr) {
          ArrayList<Integer> al = new ArrayList();
          for (int i : arr) al.add(i);
          Collections.sort(al);
          int idx = 0;
          for (int i : al) arr[idx++] = i;
      }
  
      static void sort(long[] arr) {
          ArrayList<Long> al = new ArrayList();
          for (long i : arr) al.add(i);
          Collections.sort(al);
          int idx = 0;
          for (long i : al) arr[idx++] = i;
      }
  
      static void sortDec(int[] arr) {
          ArrayList<Integer> al = new ArrayList();
          for (int i : arr) al.add(i);
          Collections.sort(al, Collections.reverseOrder());
          int idx = 0;
          for (int i : al) arr[idx++] = i;
      }
  
      static void sortDec(long[] arr) {
          ArrayList<Long> al = new ArrayList();
          for (long i : arr) al.add(i);
          Collections.sort(al, Collections.reverseOrder());
          int idx = 0;
          for (long i : al) arr[idx++] = i;
      }
  
      static class InputReader {
          private boolean finished = false;
  
          private InputStream stream;
          private byte[] buf = new byte[1024];
          private int curChar;
          private int numChars;
          private SpaceCharFilter filter;
  
          public InputReader(InputStream stream) {
              this.stream = stream;
          }
  
          public int read() {
              if (numChars == -1) {
                  throw new InputMismatchException();
              }
              if (curChar >= numChars) {
                  curChar = 0;
                  try {
                      numChars = stream.read(buf);
                  } catch (IOException e) {
                      throw new InputMismatchException();
                  }
                  if (numChars <= 0) {
                      return -1;
                  }
              }
              return buf[curChar++];
          }
  
          public int peek() {
              if (numChars == -1) {
                  return -1;
              }
              if (curChar >= numChars) {
                  curChar = 0;
                  try {
                      numChars = stream.read(buf);
                  } catch (IOException e) {
                      return -1;
                  }
                  if (numChars <= 0) {
                      return -1;
                  }
              }
              return buf[curChar];
          }
  
          public int nextInt() {
              int c = read();
              while (isSpaceChar(c)) {
                  c = read();
              }
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              int res = 0;
              do {
                  if (c < '0' || c > '9') {
                      throw new InputMismatchException();
                  }
                  res *= 10;
                  res += c - '0';
                  c = read();
              } while (!isSpaceChar(c));
              return res * sgn;
          }
  
          public long nextLong() {
              int c = read();
              while (isSpaceChar(c)) {
                  c = read();
              }
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              long res = 0;
              do {
                  if (c < '0' || c > '9') {
                      throw new InputMismatchException();
                  }
                  res *= 10;
                  res += c - '0';
                  c = read();
              } while (!isSpaceChar(c));
              return res * sgn;
          }
  
          public String nextString() {
              int c = read();
              while (isSpaceChar(c)) {
                  c = read();
              }
              StringBuilder res = new StringBuilder();
              do {
                  if (Character.isValidCodePoint(c)) {
                      res.appendCodePoint(c);
                  }
                  c = read();
              } while (!isSpaceChar(c));
              return res.toString();
          }
  
          public boolean isSpaceChar(int c) {
              if (filter != null) {
                  return filter.isSpaceChar(c);
              }
              return isWhitespace(c);
          }
  
          public static boolean isWhitespace(int c) {
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
  
          private String readLine0() {
              StringBuilder buf = new StringBuilder();
              int c = read();
              while (c != '\n' && c != -1) {
                  if (c != '\r') {
                      buf.appendCodePoint(c);
                  }
                  c = read();
              }
              return buf.toString();
          }
  
          public String readLine() {
              String s = readLine0();
              while (s.trim().length() == 0) {
                  s = readLine0();
              }
              return s;
          }
  
          public String readLine(boolean ignoreEmptyLines) {
              if (ignoreEmptyLines) {
                  return readLine();
              } else {
                  return readLine0();
              }
          }
  
          public BigInteger readBigInteger() {
              try {
                  return new BigInteger(nextString());
              } catch (NumberFormatException e) {
                  throw new InputMismatchException();
              }
          }
  
          public char nextCharacter() {
              int c = read();
              while (isSpaceChar(c)) {
                  c = read();
              }
              return (char) c;
          }
  
          public double nextDouble() {
              int c = read();
              while (isSpaceChar(c)) {
                  c = read();
              }
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              double res = 0;
              while (!isSpaceChar(c) && c != '.') {
                  if (c == 'e' || c == 'E') {
                      return res * Math.pow(10, nextInt());
                  }
                  if (c < '0' || c > '9') {
                      throw new InputMismatchException();
                  }
                  res *= 10;
                  res += c - '0';
                  c = read();
              }
              if (c == '.') {
                  c = read();
                  double m = 1;
                  while (!isSpaceChar(c)) {
                      if (c == 'e' || c == 'E') {
                          return res * Math.pow(10, nextInt());
                      }
                      if (c < '0' || c > '9') {
                          throw new InputMismatchException();
                      }
                      m /= 10;
                      res += (c - '0') * m;
                      c = read();
                  }
              }
              return res * sgn;
          }
  
          public boolean isExhausted() {
              int value;
              while (isSpaceChar(value = peek()) && value != -1) {
                  read();
              }
              return value == -1;
          }
  
          public String next() {
              return nextString();
          }
  
          public SpaceCharFilter getFilter() {
              return filter;
          }
  
          public void setFilter(SpaceCharFilter filter) {
              this.filter = filter;
          }
  
          public interface SpaceCharFilter {
              public boolean isSpaceChar(int ch);
          }
  
          public int[] nextIntArray(int n) {
              int[] array = new int[n];
              for (int i = 0; i < n; ++i) array[i] = nextInt();
              return array;
          }
  
          public int[] nextSortedIntArray(int n) {
              int array[] = nextIntArray(n);
              Arrays.sort(array);
              return array;
          }
  
          public int[] nextSumIntArray(int n) {
              int[] array = new int[n];
              array[0] = nextInt();
              for (int i = 1; i < n; ++i) array[i] = array[i - 1] + nextInt();
              return array;
          }
  
          public long[] nextLongArray(int n) {
              long[] array = new long[n];
              for (int i = 0; i < n; ++i) array[i] = nextLong();
              return array;
          }
  
          public long[] nextSumLongArray(int n) {
              long[] array = new long[n];
              array[0] = nextInt();
              for (int i = 1; i < n; ++i) array[i] = array[i - 1] + nextInt();
              return array;
          }
  
          public long[] nextSortedLongArray(int n) {
              long array[] = nextLongArray(n);
              Arrays.sort(array);
              return array;
          }
      }
  
  
  }
  