func_code_string: #include <bits/stdc++.h>   using namespace std;   bool visited[100005];   vector<long long> arr[100005];   int main() {     std::ios::sync_with_stdio(false);     long long n, x;     cin >> n;     vector<pair<long long, long long> > ans;     for (long long i = 0; i < n; i++) {       cin >> x;       arr[x].push_back(i);     }     for (long long i = 0; i < 100005; i++) {       if (arr[i].size() == 1) {         ans.push_back(make_pair(i, 0));       } else if (arr[i].size() >= 2) {         bool good = 1;         long long dif = arr[i][1] - arr[i][0];         for (long long j = 1; j < arr[i].size(); j++) {           if (arr[i][j] != arr[i][j - 1] + dif) good = 0;         }         if (good) {           ans.push_back(make_pair(i, dif));         }       }     }     cout << ans.size() << endl;     for (long long i = 0; i < ans.size(); i++)       cout << ans[i].first <<     << ans[i].second << endl;     return 0;   }   