1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
#include <bits/stdc++.h>

using ll = long long;

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
	ll n;
	std::cin >> n;
	std::vector<ll> tab(n + 1);

	ll diffsum = 0;
	ll last = 0;
	for (ll i = 0; i < n + 1; i++) {
		if (i < n) {
			std::cin >> tab[i];			
		} else {
			tab[i] = 0;
		}
		diffsum += (last - tab[i]) * i;
		last = tab[i];
	}

	std::vector<ll> possible_answers;
	for (ll i = 1; i * i <= diffsum; i++) {
		if (diffsum % i == 0) {
			if (i <= n) {
				possible_answers.push_back(i);
			}
			if (diffsum / i <= n) {
				possible_answers.push_back(diffsum / i);				
			}
		}
	}
	std::ranges::sort(possible_answers, std::greater<ll>());

	for (auto e : possible_answers) {
		std::vector<int> rests(e, 0);
		bool ok = true;

		int last2 = 0;
		for (int i = 0; i < n + 1; i++) {
			rests[i % e] += (tab[i] - last2);
			last2 = tab[i];
			if (rests[i % e] < 0) {
				ok = false;
				break;
			}
		}
		for (auto r : rests) {
			if (r != 0) {
				ok = false;
				break;
			}
		}

		if (ok) {
			std::cout << e << "\n";
			return 0;
		}
	}
}