def max_number(arr, k):
    n = len(arr)
    dp = [[0] * (k+1) for _ in range(n)]

    # Base cases
    for i in range(n):
        dp[i][0] = arr[i]

    for i in range(n):
        for j in range(1, k+1):
            for p in range(i):
                dp[i][j] = max(dp[i][j], dp[p][j-1] * 10**(i-p) + arr[p])

    return max(dp[i][k] for i in range(n))

t = int(input())
for _ in range(t):
    n, k = map(int, input().split())
    arr = list(map(int, input().split()))
    print(max_number(arr, k))