func_code_string: #include <bits/stdc++.h>   using namespace std;   const double PI = acos(-1.0);   const double EPS = 1e-11;   void fast() { std::ios_base::sync_with_stdio(0); }   vector<vector<int>> seq(1e5 + 9);   int main() {     int n, x;     cin >> n;     for (int i = 0; i < n; i++) {       scanf( %d , &x);       seq[x].push_back(i);     }     bool flag = true;     vector<pair<int, int>> ans;     for (int i = 0; i <= 1e5; i++) {       flag = true;       if (seq[i].size() == 0)         continue;       else if (seq[i].size() == 1)         ans.push_back({i, 0});       else if (seq[i].size() == 2)         ans.push_back({i, seq[i][1] - seq[i][0]});       else {         for (int j = 2; j < seq[i].size() && flag; j++) {           if (seq[i][j] - seq[i][j - 1] != seq[i][j - 1] - seq[i][j - 2])             flag = false;         }         if (flag) {           ans.push_back({i, seq[i][1] - seq[i][0]});         }       }     }     cout << ans.size() << endl;     for (int i = 0; i < ans.size(); i++) {       printf( %d %d n , ans[i].first, ans[i].second);     }     return 0;   }   