/** * @FileName f.cpp * @Author kanpurin * @Created 2020.05.15 22:44:01 **/ #include "bits/stdc++.h" using namespace std; typedef long long ll; // KMP法 O(N) // verify : https://atcoder.jp/contests/abc135/tasks/abc135_f template class KMP { public: vector pattern; int plen; vector table; // tからsを探す(sを引数に) KMP(const vector& s) : pattern(s), plen((int)pattern.size()), table(plen + 1) { table[0] = -1; int j = -1; for (int i = 0; i < plen; i++) { while (j >= 0 && pattern[i] != pattern[j]) j = table[j]; j++; if (i + 1 < plen && pattern[i + 1] == pattern[j]) table[i + 1] = table[j]; else table[i + 1] = j; } } // マッチする左端の箇所 vector search(const vector& text) { vector res; int head = 0, j = 0, tlen = (int)text.size(); while (head + j < tlen) { if (pattern[j] == text[head + j]) { if (++j != plen) continue; res.push_back(head); } head += j - table[j], j = max(table[j], 0); } return res; } }; int main() { int n;cin >> n; vector a(n); vector b(2*n); for (int i = 0; i < n; i++) { cin >> a[i]; b[i] = b[i + n] = a[i]; } sort(a.begin(), a.end()); KMP kmp(a); auto p = kmp.search(b); if (p.size() == 0) { cout << -1 << endl; } else if (p[0] == 0) { cout << 0 << endl; } else { cout << 1 << endl; } return 0; }