func_code_string: #include <bits/stdc++.h>   using namespace std;   long long suf(long long a) { return (a * (a + 1)) / 2; }   const long long OO = 1e6 + 10, MOD = 1e9 + 7;   vector<vector<int> > adj, can;   int dx[]{1, -1, 0, 0, 1, -1, 1, -1};   int dy[]{0, 0, 1, -1, 1, -1, -1, 1};   int main() {     std::ios_base::sync_with_stdio(0);     cin.tie(NULL);     cout.tie(NULL);     long long n, m, k, a, b, c, d;     string s, s1;     char ch;     while (cin >> n) {       vector<vector<int> > v(1e5 + 5);       vector<pair<int, int> > ans;       for (int i = 0; i < n; i++) {         cin >> a;         v[a].push_back(i + 1);       }       for (int i = 0; i < v.size(); i++) {         if (v[i].size() == 1)           ans.push_back({i, 0});         else if (v[i].size() > 1) {           int now = v[i][1] - v[i][0];           bool ok = true;           for (int j = 2; j < v[i].size(); j++) {             if (v[i][j] - v[i][j - 1] != now) {               ok = false;               break;             }           }           if (ok) ans.push_back({i, now});         }       }       cout << ans.size() << endl;       for (int i = 0; i < ans.size(); i++)         cout << ans[i].first <<     << ans[i].second << endl;     }     return 0;   }   