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

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

    for l in range(2, n+1):
        for i in range(n-l+1):
            j = i + l - 1
            for k in range(1, k+1):
                for p in range(k+1):
                    dp[i][j][k] = max(dp[i][j][k], dp[i][i+p-1][p] * 10**(j-i-p+1) + dp[i+p][j][k-p])

    return dp[0][n-1][k]

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