Codeforces Round 552 (Div. 3) 1154B - Make Them Equal Solution

 

Problem Link :   https://codeforces.com/contest/1154/problem/B

Solution in C++:

1. /// Author : AH_Tonmoy
2. #include <bits/stdc++.h>
3. using namespace std;
4. int32_t main() {
5. ios_base::sync_with_stdio(0);
6. cin.tie(0);
7. int n;
8. cin >> n;
9. set<int> st;
10. int x;
11. for (int i = 0; i < n; i++) {
12. int x;
13. cin >> x;
14. st.insert(x);
15. }
16. if (st.size() > 3) {
17. cout << "-1\n";
18. } else if (st.size() == 1) {
19. cout << "0\n";
20. } else if (st.size() == 2) {
21. std::vector<int> v;
22. for (auto i : st) {
23. v.push_back(i);
24. }
25. if ((v[1] - v[0]) % 2 == 0) {
26. cout << (v[1] - v[0]) / 2 << "\n";
27. } else
28. cout << v[1] - v[0] << "\n";
29. } else if (st.size() == 3) {
30. std::vector<int> v;
31. for (auto i : st) {
32. v.push_back(i);
33. }
34. if ((v[1] - v[0]) == v[2] - v[1]) {
35. cout << v[1] - v[0] << "\n";
36. } else
37. cout << "-1\n";
38. }
39. return 0;
40. }