/* author: Kite_kuma created: 2021.03.13 12:05:26 */ // #ifdef LOCAL // #define _GLIBCXX_DEBUG // #endif #include using namespace std; #pragma region macros #define foa(s, v) for(auto &s : v) #define all(v) (v).begin(), (v).end() #define rall(v) (v).rbegin(), (v).rend() #define popcnt(n) __builtin_popcountll((long long)n) #define REPname(a, b, c, d, e, ...) e #define rep(...) REPname(__VA_ARGS__, REP3, REP2, REP1, REP0)(__VA_ARGS__) #define REP0(x) for(int Counter_in_rep_macro = 0; Counter_in_rep_macro < (x); ++Counter_in_rep_macro) #define REP1(i, x) for(int i = 0; i < (x); ++i) #define REP2(i, l, r) for(int i = (l); i < (r); ++i) #define REP3(i, l, r, c) for(int i = (l); i < (r); i += (c)) #define DREPname(a, b, c, d, e, ...) e #define drep(...) DREPname(__VA_ARGS__, DREP3, DREP2, DREP1)(__VA_ARGS__) #define DREP1(i, x) for(int i = (x)-1; i >= 0; --i) #define DREP2(i, l, r) for(int i = (r)-1; i >= (l); --i) #define DREP3(i, l, r, c) for(int i = (r)-1; i >= (l); i -= (c)) #pragma endregion #pragma region aliases using ll = long long; using ld = long double; using ull = unsigned long long; using vi = std::vector; using vvi = std::vector>; using vvvi = std::vector>>; using vll = std::vector; using vvll = std::vector; using vvvll = std::vector; using pii = std::pair; using pll = std::pair; template using V = std::vector; template using VV = V>; template using VVV = V>>; template using pqup = std::priority_queue, std::greater>; template using pqdn = std::priority_queue; #pragma endregion #pragma region constants const int inf = 1e9; const long long INF = 1e18; const long double pi = acos(-1); const char dl = '\n'; const char sp = ' '; int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1}; int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1}; const int mod_1000000007 = 1000000007; const int mod_998244353 = 998244353; #pragma endregion #pragma region basic_operation template inline bool in_range(T0 x, T1 lef, T2 rig) { return ((lef <= x) && (x < rig)); } template inline bool chmin(T &a, T b) { if(a > b) { a = b; return true; } return false; } template inline bool chmax(T &a, T b) { if(a < b) { a = b; return true; } return false; } void Yes(bool f = 1) { std::cout << (f ? "Yes" : "No") << '\n'; } void No() { std::cout << "No\n"; } void YES(bool f = 1) { std::cout << (f ? "YES" : "NO") << '\n'; } void NO() { std::cout << "NO\n"; } template void drop(T answer) { std::cout << answer << '\n'; exit(0); } void err(bool flag = true) { if(!flag) return; std::cout << -1 << '\n'; exit(0); } template void vout(std::vector const &v, bool vertically = 0) { if(vertically) { for(auto const &a : v) { std::cout << a << '\n'; } return; } for(auto it = v.begin(); it != v.end(); it++) { std::cout << (*it); if(it != v.end() - 1) { std::cout << ' '; } } std::cout << '\n'; return; } inline void print() { std::cout << '\n'; } template inline void print(T x) { std::cout << x << '\n'; return; } template void print(Head H, Tail... T) { std::cout << H << " "; print(T...); } template void add(std::vector &v, T val) { for(auto &a : v) a += val; return; } template T dup(T a, T b) { assert(b != 0); return (a + b - 1) / b; } template T greatest_lower_multiple(T x, T d) { if(d == 0) return 0; if(d < 0) d *= -1; T y = x % d; if(y < 0) y += d; return x - y; } template T least_upper_multiple(T x, T d) { return -greatest_lower_multiple(-x, d); } long long POW(long long a, long long n) { long long res = 1; while(n > 0) { if(n & 1) res = res * a; a = a * a; n >>= 1; } return res; } long long modpow(long long a, long long n, long long mod) { // a^n mod assert(n >= 0 && mod); if(mod == 1) return 0LL; long long res = 1; while(n > 0) { if(n & 1) res = res * a % mod; a = a * a % mod; n >>= 1; } return res < 0 ? res + mod : res; } // return x which satisfies a * x % mod == gcd(a, mod) // not (mod | a) long long modinv(long long a, long long mod) { long long b = mod, u = 1, v = 0; while(b) { long long t = a / b; a -= t * b; std::swap(a, b); u -= t * v; std::swap(u, v); } u %= mod; if(u < 0) u += mod; return u; } template int lb(const std::vector &a, const T x) { return std::distance(a.begin(), std::lower_bound(a.begin(), a.end(), x)); } template int ub(const std::vector &a, const T x) { return std::distance(a.begin(), std::upper_bound(a.begin(), a.end(), x)); } template void unq_sort(std::vector &a) { std::sort(a.begin(), a.end()); a.erase(std::unique(a.begin(), a.end()), a.end()); } template std::vector press(std::vector &a) { auto vec = a; unq_sort(vec); std::vector ret; for(auto &v : a) ret.push_back(lb(vec, v)); return ret; } #pragma endregion #pragma region input #define VEC(type, name, size) \ vector name(size); \ scanner::INPUT(name) #define VVEC(type, name, h, w) \ vector> name(h, vector(w)); \ scanner::INPUT(name) #define INT(...) \ int __VA_ARGS__; \ scanner::INPUT(__VA_ARGS__) #define LL(...) \ long long __VA_ARGS__; \ scanner::INPUT(__VA_ARGS__) #define STR(...) \ string __VA_ARGS__; \ scanner::INPUT(__VA_ARGS__) #define CHR(...) \ char __VA_ARGS__; \ scanner::INPUT(__VA_ARGS__) #define DBL(...) \ double __VA_ARGS__; \ scanner::INPUT(__VA_ARGS__) #define LD(...) \ long double __VA_ARGS__; \ scanner::INPUT(__VA_ARGS__) #define TPL3(type0, type1, type2, name) \ std::tuple name; \ scanner::INPUT(name); #define TPL4(type0, type1, type2, type3, name) \ std::tuple name; \ scanner::INPUT(name); namespace scanner { template void scan(T &a) { std::cin >> a; } template void scan(std::pair &p) { scan(p.first); scan(p.second); } template void scan(std::tuple &p) { T0 t0; T1 t1; T2 t2; scan(t0); scan(t1); scan(t2); p = std::make_tuple(t0, t1, t2); } template void scan(std::tuple &p) { T0 t0; T1 t1; T2 t2; T3 t3; scan(t0); scan(t1); scan(t2); scan(t3); p = std::make_tuple(t0, t1, t2, t3); } template void scan(std::vector &a) { for(auto &i : a) scan(i); } void INPUT() {} template void INPUT(Head &head, Tail &...tail) { scan(head); INPUT(tail...); } } // namespace scanner template std::istream &operator>>(std::istream &is, std::pair &p) { is >> p.first >> p.second; return is; } #pragma endregion #pragma region debug #pragma region output template std::ostream &std::operator<<(std::ostream &os, const std::pair &p) { os << p.first << " " << p.second; return os; } template std::ostream &std::operator<<(std::ostream &os, const std::vector &v) { for(int i = 0; i < (int)v.size(); i++) { if(i) os << " "; os << v[i]; } return os; } #pragma endregion #pragma region view namespace viewer { void view(const long long e) { if(e == INF) std::cerr << "INF"; else if(e == -INF) std::cerr << "-INF"; else std::cerr << e; } void view(const int e) { if(e == inf) std::cerr << "inf"; else if(e == -inf) std::cerr << "-inf"; else std::cerr << e; } template void view(const T e) { std::cerr << e; } template void view(const std::pair &p) { std::cerr << "("; view(p.first); std::cerr << ", "; view(p.second); std::cerr << ")"; } template void view(const std::tuple &p) { std::cerr << "("; view(std::get<0>(p)); std::cerr << ", "; view(std::get<1>(p)); std::cerr << ", "; view(std::get<2>(p)); std::cerr << ")"; } template void view(const std::tuple &p) { std::cerr << "("; view(std::get<0>(p)); std::cerr << ", "; view(std::get<1>(p)); std::cerr << ", "; view(std::get<2>(p)); std::cerr << ", "; view(std::get<3>(p)); std::cerr << ")"; } template void view(const std::set &s) { if(s.empty()) { std::cerr << "{ }"; return; } std::cerr << "{ "; for(auto &t : s) { view(t); std::cerr << ", "; } std::cerr << "\b\b }"; } template void view(const std::unordered_set &s) { if(s.empty()) { std::cerr << "{ }"; return; } std::cerr << "{ "; for(auto &t : s) { view(t); std::cerr << ", "; } std::cerr << "\b\b }"; } template void view(const std::vector &v) { if(v.empty()) { std::cerr << "{ }"; return; } std::cerr << "{ "; for(const auto &e : v) { view(e); std::cerr << ", "; } std::cerr << "\b\b }"; } template void view(const std::vector> &vv) { std::cerr << "{\n"; for(const auto &v : vv) { std::cerr << "\t"; view(v); std::cerr << '\n'; } std::cerr << "}"; } template void view(const std::vector> &v) { std::cerr << "{\n"; for(const auto &c : v) { std::cerr << "\t("; view(c.first); std::cerr << ", "; view(c.second); std::cerr << ")\n"; } std::cerr << "}"; } template void view(const std::vector> &v) { if(v.empty()) { std::cerr << "{ }"; return; } std::cerr << '{'; for(const auto &t : v) { std::cerr << "\n\t"; view(t); std::cerr << ","; } std::cerr << "\n}"; } template void view(const std::vector> &v) { if(v.empty()) { std::cerr << "{ }"; return; } std::cerr << '{'; for(const auto &t : v) { std::cerr << "\n\t"; view(t); std::cerr << ","; } std::cerr << "\n}"; } template void view(const std::map &m) { std::cerr << "{\n"; for(const auto &t : m) { std::cerr << "\t["; view(t.first); std::cerr << "] : "; view(t.second); std::cerr << '\n'; } std::cerr << "}"; } template void view(const std::unordered_map &m) { std::cerr << "{\n"; for(const auto &t : m) { std::cerr << "\t["; view(t.first); std::cerr << "] : "; view(t.second); std::cerr << '\n'; } std::cerr << "}"; } } // namespace viewer #pragma endregion // when debugging : g++ foo.cpp -DLOCAL #ifdef LOCAL void debug_out() {} template void debug_out(Head H, Tail... T) { viewer::view(H); std::cerr << ", "; debug_out(T...); } #define debug(...) \ do { \ std::cerr << __LINE__ << " [" << #__VA_ARGS__ << "] : ["; \ debug_out(__VA_ARGS__); \ std::cerr << "\b\b]\n"; \ } while(0) #define dump(x) \ do { \ std::cerr << __LINE__ << " " << #x << " : "; \ viewer::view(x); \ std::cerr << '\n'; \ } while(0) #else #define debug(...) (void(0)) #define dump(x) (void(0)) #endif #pragma endregion int main() { std::ios::sync_with_stdio(false); std::cin.tie(nullptr); std::cout << std::fixed << std::setprecision(15); srand((unsigned)time(NULL)); INT(n); VEC(int, a, n); auto b = a; sort(all(b)); if(a == b) drop(0); drep(i, n) { if(a[i] != b[i]) { a.resize(i + 1); b.resize(i + 1); break; } } n = a.size(); int ans = 0; vector> p; rep(i, n) p.emplace_back(a[i], i); sort(all(p)); vi cyc; for(auto [val, idx] : p) { if(cyc.empty()) { cyc.push_back(idx); continue; } int front = cyc.front(), back = cyc.back(); if((front - idx + n) % n <= (back - idx + n) % n) { cyc.push_back(idx); continue; }else{ cyc = {idx}; ans++; } } if(!cyc.empty()) ans++; drop(ans); return 0; }