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.util.*;
  import java.io.*;
  
  public class Main {
  	static StringBuilder sb;
  	static dsu dsu;
  	static long fact[];
  	static int mod = (int) (1e9 + 7);
      static boolean valid(long mid,long[]arr){
          
          
          int n=arr.length;
          long[]arr1=new long[n];
          
    for(int i=0;i<n;i++){
        arr1[i]=arr[i];
        
    }
    
  long[]arr2=new long[n];
  
  for(int i=n-1;i>=2;i--) {
      
      long kp=mid-arr2[i];
      
      kp=Math.max(kp,0);
      if(arr1[i]+arr2[i]<mid){
          
          return false;}
      arr1[i]-=kp;
      long d=arr1[i]/3;
      arr2[i-1]+=d;
      arr2[i-2]+=2*d;
      
      
      
      
      
   }
  
  
  if(arr1[0]+arr2[0]>=mid&&arr2[1]+arr1[1]>=mid)return true;
  // if(mid==6)System.out.println(arr1[1]+arr2[1]);
  return false;
      
         
          
      }
  	static void solve() {
  		int n=i();
  		long[]arr=new long[n];
  		for(int i=0;i<n;i++)arr[i]=l();
  		long lo=0;
  		long hi=1000000000+2;
  		long ans=0;
  		while(lo<=hi){
  		    long mid=(lo+hi)/2;
  		    if(valid(mid,arr)){
  		        lo=mid+1;
  		        ans=Math.max(ans,mid);
  		    }
  		    else{
  		        hi=mid-1;
  		    }
  		    
  		    
  		    
  		    
  		}
  		sb.append(ans+"\n");
  	}
  
  	public static void main(String[] args) {
  		sb = new StringBuilder();
  		int test = i();
  		while (test-- > 0) {
  			solve();
  		}
  		System.out.println(sb);
  
  	}
  
  	/*
  	 * fact=new long[(int)1e6+10]; fact[0]=fact[1]=1; for(int i=2;i<fact.length;i++)
  	 * { fact[i]=((long)(i%mod)1L(long)(fact[i-1]%mod))%mod; }
  	 */
  //**************NCR%P******************	 
  	static long ncr(int n, int r) {
  		if (r > n)
  			return (long) 0;
  
  		long res = fact[n] % mod;
  		// System.out.println(res);
  		res = ((long) (res % mod) * (long) (p(fact[r], mod - 2) % mod)) % mod;
  		res = ((long) (res % mod) * (long) (p(fact[n - r], mod - 2) % mod)) % mod;
  		// System.out.println(res);
  		return res;
  
  	}
  
  	static long p(long x, long y)// POWER FXN //
  	{
  		if (y == 0)
  			return 1;
  
  		long res = 1;
  		while (y > 0) {
  			if (y % 2 == 1) {
  				res = (res * x) % mod;
  				y--;
  			}
  
  			x = (x * x) % mod;
  			y = y / 2;
  
  		}
  		return res;
  	}
  
  //**************END******************
  
  	// *************Disjoint set
  	// union*********//
  	static class dsu {
  		int parent[];
  
  		dsu(int n) {
  			parent = new int[n];
  			for (int i = 0; i < n; i++)
  				parent[i] = -1;
  		}
  
  		int find(int a) {
  			if (parent[a] < 0)
  				return a;
  			else {
  				int x = find(parent[a]);
  				parent[a] = x;
  				return x;
  			}
  		}
  
  		void merge(int a, int b) {
  			a = find(a);
  			b = find(b);
  			if (a == b)
  				return;
  			parent[b] = a;
  		}
  	}
  
  //**************PRIME FACTORIZE **********************************//
  	static TreeMap<Integer, Integer> prime(long n) {
  		TreeMap<Integer, Integer> h = new TreeMap<>();
  		long num = n;
  		for (int i = 2; i <= Math.sqrt(num); i++) {
  			if (n % i == 0) {
  				int nt = 0;
  				while (n % i == 0) {
  					n = n / i;
  					nt++;
  				}
  				h.put(i, nt);
  			}
  		}
  		if (n != 1)
  			h.put((int) n, 1);
  		return h;
  
  	}
  
  //****CLASS PAIR ************************************************
  	static class Pair implements Comparable<Pair> {
  		int x;
  		long y;
  
  		Pair(int x, long y) {
  			this.x = x;
  			this.y = y;
  		}
  
  		public int compareTo(Pair o) {
  			return (int) (this.y - o.y);
  
  		}
  
  	}
  //****CLASS PAIR **************************************************
  
  	static class InputReader {
  		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 Int() {
  			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 String String() {
  			int c = read();
  			while (isSpaceChar(c))
  				c = read();
  			StringBuilder res = new StringBuilder();
  			do {
  				res.appendCodePoint(c);
  				c = read();
  			} while (!isSpaceChar(c));
  			return res.toString();
  		}
  
  		public boolean isSpaceChar(int c) {
  			if (filter != null)
  				return filter.isSpaceChar(c);
  			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
  		}
  
  		public String next() {
  			return String();
  		}
  
  		public interface SpaceCharFilter {
  			public boolean isSpaceChar(int ch);
  		}
  	}
  
  	static class OutputWriter {
  		private final PrintWriter writer;
  
  		public OutputWriter(OutputStream outputStream) {
  			writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
  		}
  
  		public OutputWriter(Writer writer) {
  			this.writer = new PrintWriter(writer);
  		}
  
  		public void print(Object... objects) {
  			for (int i = 0; i < objects.length; i++) {
  				if (i != 0)
  					writer.print(' ');
  				writer.print(objects[i]);
  			}
  		}
  
  		public void printLine(Object... objects) {
  			print(objects);
  			writer.println();
  		}
  
  		public void close() {
  			writer.close();
  		}
  
  		public void flush() {
  			writer.flush();
  		}
  	}
  
  	static InputReader in = new InputReader(System.in);
  	static OutputWriter out = new OutputWriter(System.out);
  
  	public static long[] sort(long[] a2) {
  		int n = a2.length;
  		ArrayList<Long> l = new ArrayList<>();
  		for (long i : a2)
  			l.add(i);
  		Collections.sort(l);
  		for (int i = 0; i < l.size(); i++)
  			a2[i] = l.get(i);
  		return a2;
  	}
  
  	public static char[] sort(char[] a2) {
  		int n = a2.length;
  		ArrayList<Character> l = new ArrayList<>();
  		for (char i : a2)
  			l.add(i);
  		Collections.sort(l);
  		for (int i = 0; i < l.size(); i++)
  			a2[i] = l.get(i);
  		return a2;
  	}
  
  	public static long pow(long x, long y) {
  		long res = 1;
  		while (y > 0) {
  			if (y % 2 != 0) {
  				res = (res * x);// % modulus;
  				y--;
  
  			}
  			x = (x * x);// % modulus;
  			y = y / 2;
  		}
  		return res;
  	}
  
  //GCD___+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  	public static long gcd(long x, long y) {
  		if (x == 0)
  			return y;
  		else
  			return gcd(y % x, x);
  	}
  	// ******LOWEST COMMON MULTIPLE
  	// *********************************************
  
  	public static long lcm(long x, long y) {
  		return (x * (y / gcd(x, y)));
  	}
  
  //INPUT PATTERN********************************************************
  	public static int i() {
  		return in.Int();
  	}
  
  	public static long l() {
  		String s = in.String();
  		return Long.parseLong(s);
  	}
  
  	public static String s() {
  		return in.String();
  	}
  
  	public static int[] readArrayi(int n) {
  		int A[] = new int[n];
  		for (int i = 0; i < n; i++) {
  			A[i] = i();
  		}
  		return A;
  	}
  
  	public static long[] readArray(long n) {
  		long A[] = new long[(int) n];
  		for (int i = 0; i < n; i++) {
  			A[i] = l();
  		}
  		return A;
  	}
  
  }