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.BufferedReader;
  import java.io.InputStreamReader;
  import java.util.StringTokenizer;
  import java.util.*;
  import java.io.*;
  public class Main {
      // Graph
      // prefix sums
      // inputs
      public static void main(String args[])throws Exception{
          Input sc=new Input();
          precalculates p=new precalculates();
          StringBuilder sb=new StringBuilder();
          int t=sc.readInt();
          for(int f=0;f<t;f++){
              int n=sc.readInt();
              int a[]=sc.readArray();
              int ans=0;
              int l=0,r=1000000000;
              int mid=0;
  //            if(f==671){
  //                ArrayList<Integer> lst=new ArrayList<>();
  //                System.out.print(sb);
  //            for(int i=0;i<n;i++){
  //                System.out.print(a[i]+"-");
  //            }
              //return;
              //sb.append("\n");
                  //System.out.println(sb);
              //}
              while(l<=r){
                  mid=l+(r-l)/2;
                 // mid/=2;
                  boolean b=true;
                  int curr[]=new int[n];
                  for(int i=n-1;i>=2;i--){
                      int val=a[i];
  
                      int x=val+curr[i]-Math.min(((Math.max(val+curr[i]-mid,0))/3)*3,(a[i]/3)*3);
  //                    int y=val/3;
  //                    int mm=x+y;
  //
  //                    while(x<=y){
  //                        mm=x+y;
  //                        mm/=2;
  //                        if((curr[i]+val/3-3)>=mid && val>=3){
  //
  //                        }
  //                        val-=3;
  //                        curr[i-2]+=2;
  //                        curr[i-1]+=1;
  //                    }
                      //if()
                      curr[i-2]+=((val+curr[i]-x)/3)*2;
                      curr[i-1]+=((val+curr[i]-x)/3)*1;
                      curr[i]=x;
  
  
                  }
                  int k=Integer.MAX_VALUE;
                  curr[0]+=a[0];
                  curr[1]+=a[1];
                  for(int i=0;i<n;i++){
                      if(curr[i]<mid)
                      {
                          b=false;
                          break;
                      }
                  }
                  if(b){
                     // System.out.println(mid+"**");
                      for(int i=0;i<n;i++){
                       //   System.out.print(curr[i]+" ");
                          k=Math.min(curr[i],k);
                      }
                     // System.out.println();
                      ans=Math.max(ans,k);
                      l=mid+1;
                  }else{
                      r=mid-1;
                  }
              }
              sb.append(ans+"\n");
          }
          System.out.print(sb);
      }
  }
  /*
  1 1 6 6 1
  3 4 4 3
   */
  class Input{
      BufferedReader br;
      StringTokenizer st;
      Input(){
          br=new BufferedReader(new InputStreamReader(System.in));
          st=new StringTokenizer("");
      }
      public int[] readArray() throws Exception{
          st=new StringTokenizer(br.readLine());
          int a[]=new int[st.countTokens()];
          for(int i=0;i<a.length;i++){
              a[i]=Integer.parseInt(st.nextToken());
          }
          return a;
      }
      public long[] readArrayLong() throws Exception{
          st=new StringTokenizer(br.readLine());
          long a[]=new long[st.countTokens()];
          for(int i=0;i<a.length;i++){
              a[i]=Long.parseLong(st.nextToken());
          }
          return a;
      }
      public int readInt() throws Exception{
          st=new StringTokenizer(br.readLine());
          return Integer.parseInt(st.nextToken());
      }
      public long readLong() throws Exception{
          st=new StringTokenizer(br.readLine());
          return Long.parseLong(st.nextToken());
      }
      public String readString() throws Exception{
          return br.readLine();
      }
      public int[][] read2dArray(int n,int m)throws Exception{
          int a[][]=new int[n][m];
          for(int i=0;i<n;i++){
              st=new StringTokenizer(br.readLine());
              for(int j=0;j<m;j++){
                  a[i][j]=Integer.parseInt(st.nextToken());
              }
          }
          return a;
      }
  }
  class precalculates{
      public long gcd(long p, long q) {
          if (q == 0) return p;
          else return gcd(q, p % q);
      }
      public int[] prefixSumOneDimentional(int a[]){
          int n=a.length;
          int dp[]=new int[n];
          for(int i=0;i<n;i++){
              if(i==0)
                  dp[i]=a[i];
              else
                  dp[i]=dp[i-1]+a[i];
          }
          return dp;
      }
      public int[] postSumOneDimentional(int a[]) {
          int n = a.length;
          int dp[] = new int[n];
          for (int i = n - 1; i >= 0; i--) {
              if (i == n - 1)
                  dp[i] = a[i];
              else
                  dp[i] = dp[i + 1] + a[i];
          }
          return dp;
      }
      public int[][] prefixSum2d(int a[][]){
          int n=a.length;int m=a[0].length;
          int dp[][]=new int[n+1][m+1];
          for(int i=1;i<=n;i++){
              for(int j=1;j<=m;j++){
                  dp[i][j]=a[i-1][j-1]+dp[i-1][j]+dp[i][j-1]-dp[i-1][j-1];
              }
          }
          return dp;
      }
      public long pow(long a,long b){
          long mod=1000000007;
          long ans=1;
          if(b<=0)
              return 1;
          if(b%2==0){
              ans=pow(a,b/2)%mod;
              return ((ans%mod)*(ans%mod))%mod;
          }else{
              ans=pow(a,b-1)%mod;
              return ((a%mod)*(ans%mod))%mod;
          }
      }
  
  }
  class GraphInteger{
      HashMap<Integer,vertex> vtces;
      class vertex{
          HashMap<Integer,Integer> children;
          public vertex(){
              children=new HashMap<>();
          }
      }
      public GraphInteger(){
          vtces=new HashMap<>();
      }
      public void addVertex(int a){
          vtces.put(a,new vertex());
      }
      public void addEdge(int a,int b,int cost){
          if(!vtces.containsKey(a)){
              vtces.put(a,new vertex());
          }
          if(!vtces.containsKey(b)){
              vtces.put(b,new vertex());
          }
          vtces.get(a).children.put(b,cost);
  //        vtces.get(b).children.put(a,cost);
      }
      public boolean isCyclicDirected(){
          boolean isdone[]=new boolean[vtces.size()+1];
          boolean check[]=new boolean[vtces.size()+1];
          for(int i=1;i<=vtces.size();i++) {
              if (!isdone[i] && isCyclicDirected(i,isdone, check)) {
                  return true;
              }
          }
          return false;
      }
      private boolean isCyclicDirected(int i,boolean isdone[],boolean check[]){
          if(check[i])
              return true;
          if(isdone[i])
              return false;
          check[i]=true;
          isdone[i]=true;
          Set<Integer> set=vtces.get(i).children.keySet();
          for(Integer ii:set){
              if(isCyclicDirected(ii,isdone,check))
                  return true;
          }
          check[i]=false;
          return false;
      }
  }
  class union_find {
      int n;
      int[] sz;
      int[] par;
  
      union_find(int nval) {
          n = nval;
          sz = new int[n + 1];
          par = new int[n + 1];
          for (int i = 0; i <= n; i++) {
              par[i] = i;
              sz[i] = 1;
          }
      }
  
      int root(int x) {
          if (par[x] == x)
              return x;
          return par[x] = root(par[x]);
      }
  
      boolean find(int a, int b) {
          return root(a) == root(b);
      }
  
      int union(int a, int b) {
          int ra = root(a);
          int rb = root(b);
          if (ra == rb)
              return 0;
          if(a==b)
              return 0;
          if (sz[a] > sz[b]) {
              int temp = ra;
              ra = rb;
              rb = temp;
          }
          par[ra] = rb;
          sz[rb] += sz[ra];
          return 1;
      }
  }
  
  
  
  
  
  
  
  