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.util.*;
  
  public class C {
  
    /**
     * Template @author William Fiset, william.alexandre.fiset@gmail.com
     *
     */
    static InputReader in = new InputReader(System.in);
    private static StringBuilder sb;
  
    static class InputReader {
  
      private static final int DEFAULT_BUFFER_SIZE = 1 << 16;
      private static final InputStream DEFAULT_STREAM = System.in;
      private static final int MAX_DECIMAL_PRECISION = 21;
      private int c;
      private byte[] buf;
      private int bufferSize, bufIndex, numBytesRead;
  
      private InputStream stream;
  
      private static final byte EOF = -1;
      private static final byte NEW_LINE = 10;
      private static final byte SPACE = 32;
      private static final byte DASH = 45;
      private static final byte DOT = 46;
  
      private char[] charBuffer;
  
      private static byte[] bytes = new byte[58];
      private static int[] ints = new int[58];
      private static char[] chars = new char[128];
  
      static {
        char ch = ' ';
        int value = 0;
        byte _byte = 0;
        for (int i = 48; i < 58; i++) {
          bytes[i] = _byte++;
        }
        for (int i = 48; i < 58; i++) {
          ints[i] = value++;
        }
        for (int i = 32; i < 128; i++) {
          chars[i] = ch++;
        }
      }
  
      private static final double[][] doubles = {
        {0.0d, 0.00d, 0.000d, 0.0000d, 0.00000d, 0.000000d, 0.0000000d, 0.00000000d, 0.000000000d,
          0.0000000000d, 0.00000000000d, 0.000000000000d,
          0.0000000000000d, 0.00000000000000d, 0.000000000000000d, 0.0000000000000000d,
          0.00000000000000000d, 0.000000000000000000d,
          0.0000000000000000000d, 0.00000000000000000000d, 0.000000000000000000000d},
        {0.1d, 0.01d, 0.001d, 0.0001d, 0.00001d, 0.000001d, 0.0000001d, 0.00000001d, 0.000000001d,
          0.0000000001d, 0.00000000001d, 0.000000000001d,
          0.0000000000001d, 0.00000000000001d, 0.000000000000001d, 0.0000000000000001d,
          0.00000000000000001d, 0.000000000000000001d,
          0.0000000000000000001d, 0.00000000000000000001d, 0.000000000000000000001d},
        {0.2d, 0.02d, 0.002d, 0.0002d, 0.00002d, 0.000002d, 0.0000002d, 0.00000002d, 0.000000002d,
          0.0000000002d, 0.00000000002d, 0.000000000002d,
          0.0000000000002d, 0.00000000000002d, 0.000000000000002d, 0.0000000000000002d,
          0.00000000000000002d, 0.000000000000000002d,
          0.0000000000000000002d, 0.00000000000000000002d, 0.000000000000000000002d},
        {0.3d, 0.03d, 0.003d, 0.0003d, 0.00003d, 0.000003d, 0.0000003d, 0.00000003d, 0.000000003d,
          0.0000000003d, 0.00000000003d, 0.000000000003d,
          0.0000000000003d, 0.00000000000003d, 0.000000000000003d, 0.0000000000000003d,
          0.00000000000000003d, 0.000000000000000003d,
          0.0000000000000000003d, 0.00000000000000000003d, 0.000000000000000000003d},
        {0.4d, 0.04d, 0.004d, 0.0004d, 0.00004d, 0.000004d, 0.0000004d, 0.00000004d, 0.000000004d,
          0.0000000004d, 0.00000000004d, 0.000000000004d,
          0.0000000000004d, 0.00000000000004d, 0.000000000000004d, 0.0000000000000004d,
          0.00000000000000004d, 0.000000000000000004d,
          0.0000000000000000004d, 0.00000000000000000004d, 0.000000000000000000004d},
        {0.5d, 0.05d, 0.005d, 0.0005d, 0.00005d, 0.000005d, 0.0000005d, 0.00000005d, 0.000000005d,
          0.0000000005d, 0.00000000005d, 0.000000000005d,
          0.0000000000005d, 0.00000000000005d, 0.000000000000005d, 0.0000000000000005d,
          0.00000000000000005d, 0.000000000000000005d,
          0.0000000000000000005d, 0.00000000000000000005d, 0.000000000000000000005d},
        {0.6d, 0.06d, 0.006d, 0.0006d, 0.00006d, 0.000006d, 0.0000006d, 0.00000006d, 0.000000006d,
          0.0000000006d, 0.00000000006d, 0.000000000006d,
          0.0000000000006d, 0.00000000000006d, 0.000000000000006d, 0.0000000000000006d,
          0.00000000000000006d, 0.000000000000000006d,
          0.0000000000000000006d, 0.00000000000000000006d, 0.000000000000000000006d},
        {0.7d, 0.07d, 0.007d, 0.0007d, 0.00007d, 0.000007d, 0.0000007d, 0.00000007d, 0.000000007d,
          0.0000000007d, 0.00000000007d, 0.000000000007d,
          0.0000000000007d, 0.00000000000007d, 0.000000000000007d, 0.0000000000000007d,
          0.00000000000000007d, 0.000000000000000007d,
          0.0000000000000000007d, 0.00000000000000000007d, 0.000000000000000000007d},
        {0.8d, 0.08d, 0.008d, 0.0008d, 0.00008d, 0.000008d, 0.0000008d, 0.00000008d, 0.000000008d,
          0.0000000008d, 0.00000000008d, 0.000000000008d,
          0.0000000000008d, 0.00000000000008d, 0.000000000000008d, 0.0000000000000008d,
          0.00000000000000008d, 0.000000000000000008d,
          0.0000000000000000008d, 0.00000000000000000008d, 0.000000000000000000008d},
        {0.9d, 0.09d, 0.009d, 0.0009d, 0.00009d, 0.000009d, 0.0000009d, 0.00000009d, 0.000000009d,
          0.0000000009d, 0.00000000009d, 0.000000000009d,
          0.0000000000009d, 0.00000000000009d, 0.000000000000009d, 0.0000000000000009d,
          0.00000000000000009d, 0.000000000000000009d,
          0.0000000000000000009d, 0.00000000000000000009d, 0.000000000000000000009d}
      };
  
      public InputReader() {
        this(DEFAULT_STREAM, DEFAULT_BUFFER_SIZE);
      }
  
      public InputReader(int bufferSize) {
        this(DEFAULT_STREAM, bufferSize);
      }
  
      public InputReader(InputStream stream) {
        this(stream, DEFAULT_BUFFER_SIZE);
      }
  
      public InputReader(InputStream stream, int bufferSize) {
        if (stream == null || bufferSize <= 0) {
          throw new IllegalArgumentException();
        }
        buf = new byte[bufferSize];
        charBuffer = new char[128];
        this.bufferSize = bufferSize;
        this.stream = stream;
      }
  
      private byte read() throws IOException {
  
        if (numBytesRead == EOF) {
          throw new IOException();
        }
  
        if (bufIndex >= numBytesRead) {
          bufIndex = 0;
          numBytesRead = stream.read(buf);
          if (numBytesRead == EOF) {
            return EOF;
          }
        }
  
        return buf[bufIndex++];
      }
  
      private void doubleCharBufferSize() {
        char[] newBuffer = new char[charBuffer.length << 1];
        for (int i = 0; i < charBuffer.length; i++) {
          newBuffer[i] = charBuffer[i];
        }
        charBuffer = newBuffer;
      }
  
      private int readJunk(int token) throws IOException {
  
        if (numBytesRead == EOF) {
          return EOF;
        }
  
        do {
  
          while (bufIndex < numBytesRead) {
            if (buf[bufIndex] > token) {
              return 0;
            }
            bufIndex++;
          }
  
          numBytesRead = stream.read(buf);
          if (numBytesRead == EOF) {
            return EOF;
          }
          bufIndex = 0;
  
        } while (true);
  
      }
  
      public byte nextByte() throws IOException {
        return (byte) nextInt();
      }
  
      public int nextInt() throws IOException {
  
        if (readJunk(DASH - 1) == EOF) {
          throw new IOException();
        }
        int sgn = 1, res = 0;
  
        c = buf[bufIndex];
        if (c == DASH) {
          sgn = -1;
          bufIndex++;
        }
  
        do {
  
          while (bufIndex < numBytesRead) {
            if (buf[bufIndex] > SPACE) {
              res = (res << 3) + (res << 1);
              res += ints[buf[bufIndex++]];
            } else {
              bufIndex++;
              return res * sgn;
            }
          }
  
          numBytesRead = stream.read(buf);
          if (numBytesRead == EOF) {
            return res * sgn;
          }
          bufIndex = 0;
  
        } while (true);
  
      }
  
      public int[] nextIntArray(int n) throws IOException {
        int[] ar = new int[n];
        for (int i = 0; i < n; i++) {
          ar[i] = nextInt();
        }
        return ar;
      }
  
      public void close() throws IOException {
        stream.close();
      }
  
      public long nextLong() throws IOException {
        if (readJunk(DASH - 1) == EOF) {
          throw new IOException();
        }
        int sgn = 1;
        long res = 0L;
        c = buf[bufIndex];
        if (c == DASH) {
          sgn = -1;
          bufIndex++;
        }
        do {
          while (bufIndex < numBytesRead) {
            if (buf[bufIndex] > SPACE) {
              res = (res << 3) + (res << 1);
              res += ints[buf[bufIndex++]];
            } else {
              bufIndex++;
              return res * sgn;
            }
          }
          numBytesRead = stream.read(buf);
          if (numBytesRead == EOF) {
            return res * sgn;
          }
          bufIndex = 0;
        } while (true);
      }
  
      public String nextString() throws IOException {
        if (numBytesRead == EOF) {
          return null;
        }
        if (readJunk(SPACE) == EOF) {
          return null;
        }
  
        for (int i = 0;;) {
          while (bufIndex < numBytesRead) {
            if (buf[bufIndex] > SPACE) {
              if (i == charBuffer.length) {
                doubleCharBufferSize();
              }
              charBuffer[i++] = (char) buf[bufIndex++];
            } else {
              bufIndex++;
              return new String(charBuffer, 0, i);
            }
          }
  
          // Reload buffer
          numBytesRead = stream.read(buf);
          if (numBytesRead == EOF) {
            return new String(charBuffer, 0, i);
          }
          bufIndex = 0;
        }
      }
    }
  
    public static void main(String args[]) throws Exception {
      int t = in.nextInt();
      while (t-- != 0) {
        solve();
      }
    }
  
    static void solve() throws IOException {
      int n = in.nextInt();
      int[] arr = in.nextIntArray(n);
      int min = Integer.MAX_VALUE;
      int max = Integer.MIN_VALUE;
      for (int i = 0; i < n; i++) {
        min = Math.min(min, arr[i]);
        max = Math.max(max, arr[i]);
      }
      int res = min;
      while (min <= max) {
        int mid = min + (max - min) / 2;
        if (check(arr, mid)) {
          res = mid;
          min = mid + 1;
        } else {
          max = mid - 1;
        }
      }
      System.out.println(res);
    }
  
    static boolean check(int[] arr, int x) {
      int n = arr.length;
      long[] aux = new long[n];
      for (int i = 0; i < n; i++) {
        aux[i] = arr[i];
      }
      for (int i = n - 1; i >= 0; i--) {
        if (aux[i] < x) {
          return false;
        }
        long canGive = i < 2 ? 0 : Math.min(arr[i]/3, Math.max(0, (aux[i] - x)/3));
        if (i > 0) {
          aux[i - 1] = aux[i - 1] + canGive;
        }
        if (i > 1) {
          aux[i - 2] = aux[i - 2] + 2 * canGive;
        }
      }
      return true;
    }
  }
  /*
  1 
  3
  1 5 2
  */
  /*
  5
  3
  1 5 2
  4
  1 2 10 100
  4
  100 100 100 1
  5
  5 1 1 1 8
  6
  1 2 3 4 5 6
   */
  