func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 200009;   const int MOD = 1e9 + 7;   int main() {     ios_base::sync_with_stdio(false), cout.tie(0), cin.tie(0);     int n, k, tot;     cin >> n >> k;     tot = n;     vector<int> sta, vis(n + 2);     vis[n + 1] = 1;     int cur = 1;     vector<int> ans;     for (int i = 0; i < k; ++i) {       int t;       cin >> t;       ans.push_back(t);       sta.push_back(t);       vis[t] = 1;       tot--;       while (((int)(sta).size()) && sta.back() == cur) {         cur++;         sta.pop_back();       }     }     for (int i = 1; i < ((int)(sta).size()); ++i) {       if (sta[i] > sta[i - 1]) {         cout <<  -1 n ;         return 0;       }     }     while (tot) {       while (((int)(sta).size()) && sta.back() == cur) {         cur++;         sta.pop_back();       }       int top;       if (((int)(sta).size()) == 0)         top = n + 1;       else         top = sta.back();       for (int i = top; i >= cur; --i) {         if (!vis[i]) sta.push_back(i), tot--, ans.push_back(i);         vis[i] = 1;       }     }     for (int i : ans) cout << i <<    ;     cout <<   n ;     return 0;   }   