func_code_string: #include <bits/stdc++.h>   using namespace std;   unsigned long long int power(unsigned long long int n,                                unsigned long long int p) {     unsigned long long int m = 1;     while (p > 0) {       m *= n;       p--;     }     return m;   }   void sieveOfEratosthenes(int n, bool prime[]) {     unsigned long long int i, p;     for (i = 2; i <= n / 2; i++) {       if (prime[i]) {         for (p = i * i; p <= n; p += i) {           prime[p] = false;         }       }     }   }   void add_edge(int u, int v, vector<int> adj_list[]) {     adj_list[u - 1].push_back(v - 1);     adj_list[v - 1].push_back(u - 1);   }   int lcs(int brr[], int arr[], int size, int n) {     int dp[size + 1][n + 1];     for (int i = 0; i <= size; ++i) {       for (int j = 0; j <= n; ++j) {         if (i == 0 || j == 0)           dp[i][j] = 0;         else if (brr[i - 1] == arr[j - 1])           dp[i][j] = dp[i - 1][j - 1] + 1;         else           dp[i][j] = max(dp[i][j - 1], dp[i - 1][j]);       }     }     return dp[size][n];   }   void kmagic(int n, int k, int arr[]) {     int size = (int)1e4, count = 0;     int brr[size + 1];     unordered_set<int> st;     vector<int> v;     for (int i = 0; i < size; ++i) brr[i] = -1;     for (int i = 0; i < n; ++i) {       if (st.find(arr[i]) == st.end()) {         v.push_back(arr[i]);         st.insert(arr[i]);       }     }     count = k - v.size();     while (count > 0) {       v.push_back(v[0]);       count--;     }     if (st.size() <= k) {       for (int i = 0; i < v.size(); ++i) {         for (int j = i; j < size; j += k) brr[j] = v[i];       }       cout << size << endl;       for (int i = 0; i < size; ++i) cout << brr[i] <<    ;     } else       cout <<  -1 ;   }   int main(int argc, char const *argv[]) {     int t, x, k, y, u, v, n, m, money, val, b, days, check = 0, points;     ios_base::sync_with_stdio(false);     cin.tie(NULL);     string str;     t = 1;     cin >> t;     while (t--) {       int r, b, ox, oy, k;       string s, t;       cin >> n >> k;       unordered_set<int> st;       int heights[n];       for (int i = 0; i < n; ++i) cin >> heights[i];       kmagic(n, k, heights);       cout << endl;     }     return 0;   }   