description: 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 ⋅ 1 + 5 ⋅ 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).
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 10^4) — number of test cases.
  
  The first line of each test case contains two integers n and k (1 ≤ n ≤ 10; 1 ≤ k ≤ 10^9).
  
  The next line contains n integers a_1, a_2, ..., a_n (0 = a_1 < a_2 < ... < a_n ≤ 9).
  
  Output
  
  For each test case, print one integer — the minimum positive number of burles s that cannot be represented with k or fewer banknotes.
  
  Example
  
  Input
  
  
  4
  3 13
  0 1 2
  2 777
  0 4
  3 255
  0 1 3
  10 1000000000
  0 1 2 3 4 5 6 7 8 9
  
  
  Output
  
  
  59
  778
  148999
  999999920999999999
solution: #include <bits/stdc++.h>
  using namespace std;
  namespace FullPre {
  template <typename T>
  inline void read(T &x) {
    T f = 1;
    x = 0;
    char c = getchar();
    while (!isdigit(c)) {
      if (c == '-') f = -1;
      c = getchar();
    }
    while (isdigit(c)) {
      x = x * 10 + c - '0';
      c = getchar();
    }
    x *= f;
  }
  template <typename T, typename... args>
  inline void read(T &x, args &...Args) {
    read(x), read(Args...);
  }
  template <typename T>
  inline void write(T x) {
    if (x < 0) {
      putchar('-');
      x = -x;
    }
    if (x > 9) write(x / 10);
    putchar(x % 10 + '0');
  }
  template <typename T>
  inline void print_char(T x, char ch) {
    write(x), putchar(ch);
  }
  template <typename T>
  inline void char_print(char ch, T x) {
    putchar(ch), write(x);
  }
  template <typename T>
  inline void print_space(T x) {
    print_char(x, ' ');
  }
  template <typename T>
  inline void print_space_mul(T x) {
    print_space(x);
  }
  template <typename T, typename... args>
  inline void print_space_mul(T x, args... Args) {
    print_space(x), print_space_mul(Args...);
  }
  template <typename T>
  inline void space_print(T x) {
    char_print(' ', x);
  }
  template <typename T>
  inline void space_print_mul(T x) {
    space_print(x);
  }
  template <typename T, typename... args>
  inline void space_print_mul(T x, args... Args) {
    space_print(x), space_print_mul(Args...);
  }
  template <typename T>
  inline void println(T x) {
    print_char(x, '\n');
  }
  template <typename T>
  inline void println_mul(T x) {
    println(x);
  }
  template <typename T, typename... args>
  inline void println_mul(T x, args... Args) {
    println(x), println_mul(Args...);
  }
  template <typename T>
  inline void lnprint(T x) {
    char_print('\n', x);
  }
  template <typename T>
  inline void lnprint_mul(T x) {
    lnprint(x);
  }
  template <typename T, typename... args>
  inline void lnprint_mul(T x, args... Args) {
    lnprint(x), lnprint_mul(Args...);
  }
  inline void filein(string s) { freopen((s + ".in").c_str(), "r", stdin); }
  inline void fileout(string s) { freopen((s + ".out").c_str(), "w", stdout); }
  inline void file(string s) { filein(s), fileout(s); }
  template <typename T>
  inline T mymin(T a, T b) {
    return a < b ? a : b;
  }
  template <typename T, typename... args>
  inline T mymin(T a, T b, args... Args) {
    return mymin(mymin(a, b), Args...);
  }
  template <typename T>
  inline T mymax(T a, T b) {
    return a > b ? a : b;
  }
  template <typename T, typename... args>
  inline T mymax(T a, T b, args... Args) {
    return mymax(mymax(a, b), Args...);
  }
  template <typename T>
  inline T myabs(T a) {
    return a < 0 ? -a : a;
  }
  template <typename T>
  inline T mysq(T a) {
    return a * a;
  }
  template <typename T>
  inline T mygcd(T a, T b) {
    return !b ? a : mygcd(b, a % b);
  }
  template <typename T, typename... args>
  inline T mygcd(T a, T b, args... Args) {
    return mygcd(mygcd(a, b), Args...);
  }
  template <typename T>
  inline T mylcm(T a, T b) {
    return a / mygcd(a, b) * b;
  }
  template <typename T, typename... args>
  inline T mylcm(T a, T b, args... Args) {
    return mylcm(mylcm(a, b), Args...);
  }
  template <typename T>
  inline T myswap(T &a, T &b) {
    a ^= b ^= a ^= b;
  }
  }  // namespace FullPre
  using namespace FullPre;
  namespace Solution {
  const long long N = 17;
  long long n, k, a[N], pw[N];
  inline void Main() {
    pw[0] = 1;
    for (long long(i) = (1); (i) <= (14); ++(i)) pw[i] = pw[i - 1] * 10;
    long long Test;
    read(Test);
    while (Test--) {
      read(n, k);
      for (long long(i) = (1); (i) <= (n); ++(i)) read(a[i]);
      long long sum = 0;
      bool fl = 0;
      string ans = "";
      for (long long(i) = (1); (i) <= (n - 1); ++(i)) {
        if (sum + pw[a[i + 1] - a[i]] - 1 <= k) {
          sum += pw[a[i + 1] - a[i]] - 1;
          for (long long(j) = (a[i]); (j) <= (a[i + 1] - 1); ++(j)) ans += "9";
          continue;
        }
        fl = 1;
        write(k - sum + 1), cout << ans << endl;
        break;
      }
      if (fl) continue;
      write(k - sum + 1), cout << ans << endl;
    }
    return;
  }
  }  // namespace Solution
  int main() {
    Solution ::Main();
    return 0;
  }
  