func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long int mxn = 1e5 + 5;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     long long int t = 1;     while (t--) {       long long int i, j, k, n, m;       cin >> n;       map<long long int, long long int> mp, diff;       for (i = 0; i < n; i++) {         cin >> k;         if (mp.find(k) == mp.end())           mp[k] = i, diff[k] = 0;         else if (diff[k] == 0 || i - mp[k] == diff[k]) {           if (diff[k] == 0) diff[k] = i - mp[k];           mp[k] = i;         } else           diff[k] = -1;       }       set<pair<long long int, long long int> > ans;       for (auto i : diff)         if (i.second != -1) ans.insert(make_pair(i.first, i.second));       cout << ans.size() <<   n ;       for (auto i : ans) cout << i.first <<     << i.second <<   n ;     }     return 0;   }   