func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     int a[n];     vector<pair<int, int>> v;     set<int> s;     for (int i = 0; i < n; i++) {       cin >> a[i];       v.push_back(make_pair(a[i], i));       s.insert(a[i]);     }     int m = s.size();     sort(v.begin(), v.end());     vector<int> r;     for (auto i : s) {       r.push_back(i);     }     if (n == 1) {       cout << 1 << endl;       cout << a[0] <<     << 0;     } else {       int x = 0;       vector<vector<int>> p(m);       for (int i = 0; i < n; i++) {         if (i == 0 || v[i].first == v[i - 1].first) {           p[x].push_back(v[i].second);         } else {           x++;           p[x].push_back(v[i].second);         }       }       vector<pair<int, int>> o;       for (int i = 0; i < m; i++) {         if (p[i].size() == 1) {           o.push_back(make_pair(r[i], 0));         } else {           bool f = true;           int x = p[i][1] - p[i][0];           for (int j = 2; j < p[i].size(); j++) {             if ((p[i][j - 1] + x) != p[i][j]) {               f = false;               break;             }           }           if (f == true) {             o.push_back(make_pair(r[i], x));           }         }       }       cout << o.size() << endl;       for (int i = 0; i < o.size(); i++) {         cout << o[i].first <<     << o[i].second << endl;       }     }   }   