def fun(d):
    res = ""
    for k, v in d.items():
        res += f"{k}" * v
    return int(res)


t = int(input())
for _ in range(t):
    m = int(input())
    d = dict(
        {i + 1: v for i, v in enumerate([*map(int, input().split())]) if v != 0}
    )
    print(m * fun(d))