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: // हर हर महादेव
  import java.util.*;
  import java.lang.*;
  import java.io.*;
  import java.math.BigInteger;
  import java.text.DecimalFormat;
  
  public final class Solution {
  
      static int inf = Integer.MAX_VALUE;
      static long mod = 1000000000 + 7;
    
   static void ne(Scanner sc, BufferedWriter op) throws Exception {
        int n=sc.nextInt();
        long[] arr= new long[n];
        for(int i=0;i<n;i++){
            arr[i]=sc.nextLong();
  
        }
      //   int[] arr= new int[n];
        long l=0;
        long r=1000000000;
        long ans=0;
        while(l<=r){
           long mid=(l+r)/2;
          //  print(mid);
           if(check(mid,arr)){
              //  print(mid);
               ans=mid;
               l=mid+1;
           }else{
               r=mid-1;
           }
        }
       
       op.write(ans+"\n");
       
  
   }
  
   static boolean check(long val , long[] values){
      int n=values.length;
      long[] arr= new long[n];
      for(int i=0;i<n;i++){
          arr[i]=values[i];
      }
      for(int i=n-1;i>=2;i--){
          long d=(arr[i]-val)/3;
          if(d<0){
              continue;
          }
          if(values[i]>=3*d){
            arr[i]-=(3*d);
            arr[i-1]+=d;
            arr[i-2]+=(2*d);
  
          }else{
              long dd=(values[i])/3;
              arr[i]-=(3*dd);
              arr[i-1]+=(dd);
              arr[i-2]+=(2*dd);
          }
  
      }
      long min=(long)inf;
      for(int i=0;i<n;i++){
        min=Math.min(arr[i],min);
      }
      if(min>=val){
          return true;
      }
      return false;
  
  
  
   }
  
  
  
    
      
    
  
      public static void main(String[] args) throws Exception {
          BufferedWriter op = new BufferedWriter(new OutputStreamWriter(System.out));
          // Reader sc = new Reader();
       
          Scanner sc= new Scanner(System.in);
          int t = sc.nextInt();
          while (t-->0){ ne(sc, op); }
          
          // ne(sc,op);
             
                     
          op.flush();
      }
  
      static void print(Object o) {
          System.out.println(String.valueOf(o));
      }
      static int[] toIntArr(String s){
          int[] val= new int[s.length()];
          for(int i=0;i<s.length();i++){
              val[i]=s.charAt(i)-'a';
          }
          return val;
      }
  
      static void  sort(int[] arr){
          ArrayList<Integer> list= new ArrayList<>();
          for(int i=0;i<arr.length;i++){
              list.add(arr[i]);
  
          }
          Collections.sort(list);
          for(int i=0;i<arr.length;i++){
              arr[i]=list.get(i);
          }
      }
         static void  sort(long[] arr){
          ArrayList<Long> list= new ArrayList<>();
          for(int i=0;i<arr.length;i++){
              list.add(arr[i]);
  
          }
          Collections.sort(list);
          for(int i=0;i<arr.length;i++){
              arr[i]=list.get(i);
          }
      }
  
  }
  //NENENENENENENENE END MAIN CLASS NENENENENENENNENENE
  
  //  class seg  {
  //      int x1;
  //      int x2;
  //      int x3;
  //      int x4;
  //      public seg(int x1, int x2,int x3, int x4){
  //          this.x1=x1;
  //          this.x2=x2;
  //          this.x3=x3;
  //          this.x4=x4;
  //      }
  
  // //    @Override
  //     public boolean equals(seg obj)
  //     {
  //         if(x1==obj.x1 && x2==obj.x2 && x3==obj.x3 && x4==obj.x4){
  //             return true;
  //         }
  //         if(x1==obj.x3 && x2==obj.x4 && x3==obj.x1 && x4==obj.x2){
  //             return true;
  //         }
           
  //         return false;   
        
  //     }
  //     @Override
  //     public String toString(){
  //         return "[ "+x1+" "+x2+" "+x3+" "+x4+" ]";
  //     } 
           
  //     // @Override
  //     // public int hashCode(seg s){
  //     //     return super.hashCode();
  //     //     // int h=17;
  //     //     // Integer one=new Integer(s.x1);
  //     //     // Integer two=new Integer(s.x2);
  //     //     // Integer three=new Integer(s.x3);
  //     //     // Integer four=new Integer(s.x4);
  //     //     // h=31*h+one.hashCode();
  //     //     // h=31*h+two.hashCode();
  //     //     // h=31*h+three.hashCode();
  //     //     // h=31*h+four.hashCode();
  //     //     // return h;
  //     // }
     
  //  }
   
  
  // return -1 to put no ahed in array
  class pair {
      int  xx;
      int yy;
      pair(int xx, int yy ) {
          this.xx = xx;
          this.yy = yy;
      }
      public String toString(){
          return "["+xx+"-"+yy+"]";
      }
  }
  
  
  class sortY implements Comparator<pair> {
      public int compare(pair p1, pair p2) {
          if (p1.yy > p2.yy) {
              return 1;
          } else if (p1.yy == p2.yy) {
              if (p1.xx > p2.xx) {
                  return 1;
              } else if (p1.xx < p2.xx) {
                  return -1;
              }
              return 0;
  
          }
          return -1;
      }
  }
  
  class sortX implements Comparator<pair> {
      public int compare(pair p1, pair p2) {
          if (p1.xx > p2.xx) {
              return 1;
          } else if (p1.xx == p2.xx) {
              if (p1.yy > p2.yy) {
                  return 1;
              } else if (p1.yy < p2.yy) {
                  return -1;
              }
              return 0;
  
          }
          return -1;
      }
  }
  
  class debug {
  
      static void print1d(long[] arr) {
          System.out.println();
          for (int i = 0; i < arr.length; i++) {
              System.out.print(arr[i] + " ");
          }
  
      }
  
      static void print1d(int[] arr) {
          System.out.println();
          for (int i = 0; i < arr.length; i++) {
              System.out.println(i+" = "+arr[i]);
          }
  
      }
  
      static void print1d(boolean[] arr) {
          System.out.println();
          for (int i = 0; i < arr.length; i++) {
              System.out.println(i + "= " + arr[i]);
          }
  
      }
  
      static void print2d(int[][] arr) {
          System.out.println();
          int n = arr.length;
          int n2 = arr[0].length;
          for (int i = 0; i < n; i++) {
              for (int j = 0; j < n2; j++) {
                  System.out.print(arr[i][j] + " ");
              }
              System.out.println();
          }
  
      }
         static void print2d(boolean[][] arr) {
          System.out.println();
          int n = arr.length;
          int n2 = arr[0].length;
          for (int i = 0; i < n; i++) {
              for (int j = 0; j < n2; j++) {
                  System.out.print(arr[i][j] + " ");
              }
              System.out.println();
          }
  
      }
  
      static void print2d(long[][] arr) {
          System.out.println();
          int n = arr.length;
          int n2 = arr[0].length;
          for (int i = 0; i < n; i++) {
              for (int j = 0; j < n2; j++) {
                  System.out.print(arr[i][j] + " ");
              }
              System.out.println();
          }
  
      }
       static void printPair(ArrayList<pair> list) {
          if(list.size()==0){
              System.out.println("empty list");
              return;
          }
         System.out.println();
         for(int i=0;i<list.size();i++){
            System.out.println(list.get(i).xx+"-"+list.get(i).yy);
         }
      }
  
  }
  
  class Reader {
      final private int BUFFER_SIZE = 1 << 16;
      private DataInputStream din;
      private byte[] buffer;
      private int bufferPointer, bytesRead;
  
      public Reader() {
          din = new DataInputStream(System.in);
          buffer = new byte[BUFFER_SIZE];
          bufferPointer = bytesRead = 0;
      }
  
      public Reader(String file_name) throws IOException {
          din = new DataInputStream(new FileInputStream(file_name));
          buffer = new byte[BUFFER_SIZE];
          bufferPointer = bytesRead = 0;
      }
  
      public String readLine() throws IOException {
          byte[] buf = new byte[64]; // line length
          int cnt = 0, c;
          while ((c = read()) != -1) {
              if (c == '\n') {
                  if (cnt != 0) {
                      break;
                  } else {
                      continue;
                  }
              }
              buf[cnt++] = (byte) c;
          }
          return new String(buf, 0, cnt);
      }
  
      public int nextInt() throws IOException {
          int ret = 0;
          byte c = read();
          while (c <= ' ') {
              c = read();
          }
          boolean neg = (c == '-');
          if (neg)
              c = read();
          do {
              ret = ret * 10 + c - '0';
          } while ((c = read()) >= '0' && c <= '9');
  
          if (neg)
              return -ret;
          return ret;
      }
  
      public long nextLong() throws IOException {
          long ret = 0;
          byte c = read();
          while (c <= ' ')
              c = read();
          boolean neg = (c == '-');
          if (neg)
              c = read();
          do {
              ret = ret * 10 + c - '0';
          } while ((c = read()) >= '0' && c <= '9');
          if (neg)
              return -ret;
          return ret;
      }
  
      public double nextDouble() throws IOException {
          double ret = 0, div = 1;
          byte c = read();
          while (c <= ' ')
              c = read();
          boolean neg = (c == '-');
          if (neg)
              c = read();
  
          do {
              ret = ret * 10 + c - '0';
          } while ((c = read()) >= '0' && c <= '9');
  
          if (c == '.') {
              while ((c = read()) >= '0' && c <= '9') {
                  ret += (c - '0') / (div *= 10);
              }
          }
  
          if (neg)
              return -ret;
          return ret;
      }
  
      private void fillBuffer() throws IOException {
          bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
          if (bytesRead == -1)
              buffer[0] = -1;
      }
  
      private byte read() throws IOException {
          if (bufferPointer == bytesRead)
              fillBuffer();
          return buffer[bufferPointer++];
      }
  
      public void close() throws IOException {
          if (din == null)
              return;
          din.close();
      }
  }
   class MultiTreeSet<E> {
  	TreeMap<E, Integer> freqTreeMap = new TreeMap<E, Integer>();
  	int size;
   
  	public MultiTreeSet() {}
   
  	public MultiTreeSet(Collection<? extends E> c) {
  		for(E element : c)
  			add(element);
  	}
   
  	public int size() {
  		return size;
  	}
   
  	public void add(E element) {
  		Integer freq = freqTreeMap.get(element);
  		if(freq==null)
  			freqTreeMap.put(element, 1);
  		else
  			freqTreeMap.put(element,freq+1);
  		++size;
  	}
   
  	public void remove(E element) {
  		Integer freq = freqTreeMap.get(element);
  		if(freq!=null) {
  			if(freq==1)
  				freqTreeMap.remove(element);
  			else
  				freqTreeMap.put(element, freq-1);
  			--size;
  		}
  	}
   
  	public int get(E element) {
  		Integer freq = freqTreeMap.get(element);
  		if(freq==null)
  			return 0;
  		return freq;
  	}
   
  	public boolean contains(E element) {
  		return get(element)>0;
  	}
   
  	public boolean isEmpty() {
  		return size==0;
  	}
   
  	public E first() {
  		return freqTreeMap.firstKey();
  	}
   
  	public E last() {
  		return freqTreeMap.lastKey();
  	}
   
  	public E ceiling(E element) {
  		return freqTreeMap.ceilingKey(element);
  	}
   
  	public E floor(E element) {
  		return freqTreeMap.floorKey(element);
  	}
   
  	public E higher(E element) {
  		return freqTreeMap.higherKey(element);
  	}
   
  	public E lower(E element) {
  		return freqTreeMap.lowerKey(element);
  	}
  }
   