C. Banknotes
greedy; number theory
In Berland, \(n\) different types of banknotes are used. Banknotes of the \(i\)-th type have denomination \(10^{a_i}\) burles (burles are the currency used in Berland); the denomination of banknotes of the first type is exactly \(1\).Let's denote \(f(s)\) as the minimum number of banknotes required to represent exactly \(s\) burles. For example, if the denominations of banknotes used in Berland are \(1\), \(10\) and \(100\), then \(f(59) = 14\): \(9\) banknotes with denomination of \(1\) burle and \(5\) banknotes with denomination of \(10\) burles can be used to represent exactly \(9 \cdot 1 + 5 \cdot 10 = 59\) burles, and there's no way to do it with fewer banknotes.For a given integer \(k\), find the minimum positive number of burles \(s\) that cannot be represented with \(k\) or fewer banknotes (that is, \(f(s) > k\)).
The first line contains a single integer \(t\) (\(1 \le t \le 10^4\)) — number of test cases.The first line of each test case contains two integers \(n\) and \(k\) (\(1 \le n \le 10; 1 \le k \le 10^9\)).The next line contains \(n\) integers \(a_1, a_2, \dots, a_n\) (\(0 = a_1 < a_2 < \dots < a_n \le 9\)).
For each test case, print one integer — the minimum positive number of burles \(s\) that cannot be represented with \(k\) or fewer banknotes.