#ifndef LOCAL #define FAST_IO #endif #define INT128 // ============ #include #define OVERRIDE(a, b, c, d, ...) d #define REP2(i, n) for (i32 i = 0; i < (i32)(n); ++i) #define REP3(i, m, n) for (i32 i = (i32)(m); i < (i32)(n); ++i) #define REP(...) OVERRIDE(__VA_ARGS__, REP3, REP2)(__VA_ARGS__) #define PER2(i, n) for (i32 i = (i32)(n)-1; i >= 0; --i) #define PER3(i, m, n) for (i32 i = (i32)(n)-1; i >= (i32)(m); --i) #define PER(...) OVERRIDE(__VA_ARGS__, PER3, PER2)(__VA_ARGS__) #define ALL(x) begin(x), end(x) #define LEN(x) (i32)(x.size()) using namespace std; using u32 = unsigned int; using u64 = unsigned long long; using i32 = signed int; using i64 = signed long long; using f64 = double; using f80 = long double; using pi = pair; using pl = pair; template using V = vector; template using VV = V>; template using VVV = V>>; template using VVVV = V>>>; template using PQR = priority_queue, greater>; template bool chmin(T &x, const T &y) { if (x > y) { x = y; return true; } return false; } template bool chmax(T &x, const T &y) { if (x < y) { x = y; return true; } return false; } template i32 lob(const V &arr, const T &v) { return (i32)(lower_bound(ALL(arr), v) - arr.begin()); } template i32 upb(const V &arr, const T &v) { return (i32)(upper_bound(ALL(arr), v) - arr.begin()); } template V argsort(const V &arr) { V ret(arr.size()); iota(ALL(ret), 0); sort(ALL(ret), [&](i32 i, i32 j) -> bool { if (arr[i] == arr[j]) { return i < j; } else { return arr[i] < arr[j]; } }); return ret; } #ifdef INT128 using u128 = __uint128_t; using i128 = __int128_t; #endif [[maybe_unused]] constexpr i32 INF = 1000000100; [[maybe_unused]] constexpr i64 INF64 = 3000000000000000100; struct SetUpIO { SetUpIO() { #ifdef FAST_IO ios::sync_with_stdio(false); cin.tie(nullptr); #endif cout << fixed << setprecision(15); } } set_up_io; void scan(char &x) { cin >> x; } void scan(u32 &x) { cin >> x; } void scan(u64 &x) { cin >> x; } void scan(i32 &x) { cin >> x; } void scan(i64 &x) { cin >> x; } void scan(f64 &x) { cin >> x; } void scan(string &x) { cin >> x; } template void scan(V &x) { for (T &ele : x) { scan(ele); } } void read() {} template void read(Head &head, Tail &...tail) { scan(head); read(tail...); } #define CHAR(...) \ char __VA_ARGS__; \ read(__VA_ARGS__); #define U32(...) \ u32 __VA_ARGS__; \ read(__VA_ARGS__); #define U64(...) \ u64 __VA_ARGS__; \ read(__VA_ARGS__); #define I32(...) \ i32 __VA_ARGS__; \ read(__VA_ARGS__); #define I64(...) \ i64 __VA_ARGS__; \ read(__VA_ARGS__); #define F64(...) \ f64 __VA_ARGS__; \ read(__VA_ARGS__); #define STR(...) \ string __VA_ARGS__; \ read(__VA_ARGS__); #define VEC(type, name, size) \ V name(size); \ read(name); #define VVEC(type, name, size1, size2) \ VV name(size1, V(size2)); \ read(name); // ============ #ifdef DEBUGF #else #define DBG(...) (void)0 #endif // ============ #include #include #if defined(LOCAL) || defined(FIX_SEED) std::mt19937_64 mt(123456789); #else std::mt19937_64 mt(std::chrono::steady_clock::now().time_since_epoch().count()); #endif template T uniform(T l, T r) { return std::uniform_int_distribution(l, r - 1)(mt); } template T uniform(T n) { return std::uniform_int_distribution(0, n - 1)(mt); } // ============ i32 get(const V &p, i32 i) { i %= LEN(p); if (i < 0) { i += LEN(p); } return p[i]; } i32 f(V p) { i32 n = LEN(p); i32 mn = (i32)(min_element(ALL(p)) - begin(p)); if (n % 4 == 0) { if (get(p, mn - 1) < get(p, mn + 1)) { mn = (mn + n - 1) % n; } } bool f1 = true, f2 = true; if (n % 4 == 0) { f1 = get(p, mn - 1) < get(p, mn + 2); f2 = get(p, mn + n / 2 - 1) < get(p, mn + n / 2 + 2); } else { f1 = get(p, mn - 1) < get(p, mn + 1); f2 = get(p, mn + n / 2 - 1) < get(p, mn + n / 2 + 1); } if (f1 == f2) { return (mn + n - (n - 1) / 4) % n; } else { return (mn + n + n / 2 - (n - 1) / 4) % n; } } bool test(V p, i32 r) { i32 n = LEN(p); i32 i1 = f(p); set x; REP(i, n / 2) { x.insert(get(p, i1 + i)); } REP(i, n / 4) { i32 a = (i1 + i) % n; i32 b = (i1 + n / 2 - 1 - i) % n; swap(p[a], p[b]); } rotate(begin(p), begin(p) + r, end(p)); i32 i2 = f(p); REP(i, n / 2) { if (x.contains(get(p, i2 + i))) { return false; } } return true; } void gen() { i32 n = uniform(3, 7) * 2; V p(n); iota(ALL(p), 0); shuffle(ALL(p), mt); i32 r = uniform(n); DBG(p, r); if (!test(p, r)) { cerr << "FAIL\n"; exit(0); } } void test() { REP(iter, 100) { gen(); } cerr << "OK\n"; } void solve() { I32(n); VEC(i32, p, n); cout << f(p) << endl; } int main() { i32 t = 1; cin >> t; while (t--) { solve(); } }