#include #include using namespace std; // 小さいNの場合に使う単純な回文判定 bool simpleCheck(const vector& S, int N) { int size = S.size(); // 奇数長回文チェック for (int center = 0; center < size; ++center) { int length = 0; while (center - length >= 0 && center + length < size && (S[center - length] == S[center + length] || S[center - length] == -1 || S[center + length] == -1)) { ++length; } if ((2 * length - 1) > N) return true; } // 偶数長回文チェック for (int center = 0; center + 1 < size; ++center) { int length = 0; while (center - length >= 0 && center + length + 1 < size && (S[center - length] == S[center + length + 1] || S[center - length] == -1 || S[center + length + 1] == -1)) { ++length; } if (2 * length > N) return true; } return false; } // 大きいNの場合に使う高速化された回文判定 bool optimizedCheck(const vector& S, int N) { int size = S.size(); // Manacher法を使って回文長を高速に計算 vector palindrome(size, 0); int center = 0, right = 0; for (int i = 0; i < size; ++i) { int mirror = 2 * center - i; if (i < right) palindrome[i] = min(right - i, palindrome[mirror]); // 回文の拡張 while (i + palindrome[i] < size && i - palindrome[i] >= 0 && (S[i + palindrome[i]] == S[i - palindrome[i]] || S[i + palindrome[i]] == -1 || S[i - palindrome[i]] == -1)) { palindrome[i]++; } // 回文の右端を更新 if (i + palindrome[i] > right) { center = i; right = i + palindrome[i]; } // 回文長がNを超える場合、すぐに返す if (2 * palindrome[i] - 1 > N || 2 * palindrome[i] > N) return true; } return false; } int main() { ios::sync_with_stdio(false); cin.tie(0); int N; cin >> N; vector A(2 * N); for (int i = 0; i < 2 * N; ++i) { cin >> A[i]; } // AA = A + A(連結) vector AA(4 * N); for (int i = 0; i < 2 * N; ++i) { AA[i] = A[i]; AA[i + 2 * N] = A[i]; } // Nが大きいか小さいかで分岐 if (N <= 1000) { cout << (simpleCheck(AA, N) ? "Yes" : "No") << '\n'; } else { cout << (optimizedCheck(AA, N) ? "Yes" : "No") << '\n'; } return 0; }