N=int(input())
for _ in range(N):
  M=int(input())
  A=list(map(int, input().split()))
  B=[]
  for i in range(9):
    for j in range(A[i]):
      B.append(str(i+1))
  if len(B)==0:
    print(M)
  else:
    b=int(''.join(B))
    print(b*M)