description: It is a complicated version of problem F1. The difference between them is the constraints (F1: k ≤ 2, F2: k ≤ 10).
  
  You are given an integer n. Find the minimum integer x such that x ≥ n and the number x is k-beautiful.
  
  A number is called k-beautiful if its decimal representation having no leading zeroes contains no more than k different digits. E.g. if k = 2, the numbers 3434443, 55550, 777 and 21 are k-beautiful whereas the numbers 120, 445435 and 998244353 are not.
  
  Input
  
  The first line contains one integer t (1 ≤ t ≤ 10^4) — the number of test cases. Then t test cases follow.
  
  Each test case consists of one line containing two integers n and k (1 ≤ n ≤ 10^9, 1 ≤ k ≤ 10).
  
  Output
  
  For each test case output on a separate line x — the minimum k-beautiful integer such that x ≥ n.
  
  Example
  
  Input
  
  
  6
  2021 3
  177890 2
  34512 3
  724533 4
  998244353 1
  12345678 10
  
  
  Output
  
  
  2021
  181111
  34533
  724542
  999999999
  12345678
solution: #include <bits/stdc++.h>
  using namespace std;
  int main() {
    int t, n, k, k_c, i, left_max, smallest_uniq;
    vector<int> v, uniq;
    cin >> t;
    while (t) {
      cin >> n >> k;
      k_c = k;
      v.clear();
      uniq.clear();
      while (n > 0) {
        v.push_back(n % 10);
        n = n / 10;
      }
      i = v.size() - 1;
      for (; - 1 < i && k > 0; i--) {
        if (find(uniq.begin(), uniq.end(), v[i]) == uniq.end()) {
          uniq.push_back(v[i]);
          k -= 1;
        }
      }
      if (i > -1) {
        left_max = *max_element(v.begin(), v.begin() + i);
        smallest_uniq = *min_element(uniq.begin(), uniq.end());
      }
      int smallest_high = 10, flag = 0, target;
      while (i > -1) {
        if (flag)
          v[i] = smallest_uniq;
        else if (find(uniq.begin(), uniq.end(), v[i]) == uniq.end()) {
          for (int j = 0; j < uniq.size(); j++) {
            if (v[i] < uniq[j] && uniq[j] < smallest_high) {
              smallest_high = uniq[j];
              flag = 1;
            }
          }
          if (flag == 0) {
            target = v[i + 1];
            if (find(uniq.begin(), uniq.end(), target + 1) != uniq.end()) {
              i += 1;
              v[i] += 1;
              if (find(v.begin() + i, v.end(), target) == v.end())
                smallest_uniq = 0;
            } else {
              k = k_c + 1;
              for (int j = i + 1; k > k_c; j += 1) {
                k = k_c + 1;
                while (v[j] < 10 && k > k_c) {
                  v[j] += 1;
                  uniq.clear();
                  k = 0;
                  for (int z = j; z < v.size(); z++)
                    if (find(uniq.begin(), uniq.end(), v[z]) == uniq.end()) {
                      uniq.push_back(v[z]);
                      k += 1;
                    }
                  smallest_uniq = *min_element(uniq.begin(), uniq.end());
                  if (k < k_c) smallest_uniq = 0;
                }
                i = j;
              }
            }
            flag = 1;
          } else
            v[i] = smallest_high;
        }
        i -= 1;
      }
      for (i = v.size() - 1; - 1 < i; i--) cout << v[i];
      cout << endl;
      t--;
    }
    return 0;
  }
  