#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using Int = long long; template ostream &operator<<(ostream &os, const pair &a) { return os << "(" << a.first << ", " << a.second << ")"; }; template void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; } template bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; } template bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; } //////////////////////////////////////////////////////////////////////////////// template struct ModInt { static constexpr unsigned M = M_; unsigned x; constexpr ModInt() : x(0U) {} constexpr ModInt(unsigned x_) : x(x_ % M) {} constexpr ModInt(unsigned long long x_) : x(x_ % M) {} constexpr ModInt(int x_) : x(((x_ %= static_cast(M)) < 0) ? (x_ + static_cast(M)) : x_) {} constexpr ModInt(long long x_) : x(((x_ %= static_cast(M)) < 0) ? (x_ + static_cast(M)) : x_) {} ModInt &operator+=(const ModInt &a) { x = ((x += a.x) >= M) ? (x - M) : x; return *this; } ModInt &operator-=(const ModInt &a) { x = ((x -= a.x) >= M) ? (x + M) : x; return *this; } ModInt &operator*=(const ModInt &a) { x = (static_cast(x) * a.x) % M; return *this; } ModInt &operator/=(const ModInt &a) { return (*this *= a.inv()); } ModInt pow(long long e) const { if (e < 0) return inv().pow(-e); ModInt a = *this, b = 1U; for (; e; e >>= 1) { if (e & 1) b *= a; a *= a; } return b; } ModInt inv() const { unsigned a = M, b = x; int y = 0, z = 1; for (; b; ) { const unsigned q = a / b; const unsigned c = a - q * b; a = b; b = c; const int w = y - static_cast(q) * z; y = z; z = w; } assert(a == 1U); return ModInt(y); } ModInt operator+() const { return *this; } ModInt operator-() const { ModInt a; a.x = x ? (M - x) : 0U; return a; } ModInt operator+(const ModInt &a) const { return (ModInt(*this) += a); } ModInt operator-(const ModInt &a) const { return (ModInt(*this) -= a); } ModInt operator*(const ModInt &a) const { return (ModInt(*this) *= a); } ModInt operator/(const ModInt &a) const { return (ModInt(*this) /= a); } template friend ModInt operator+(T a, const ModInt &b) { return (ModInt(a) += b); } template friend ModInt operator-(T a, const ModInt &b) { return (ModInt(a) -= b); } template friend ModInt operator*(T a, const ModInt &b) { return (ModInt(a) *= b); } template friend ModInt operator/(T a, const ModInt &b) { return (ModInt(a) /= b); } explicit operator bool() const { return x; } bool operator==(const ModInt &a) const { return (x == a.x); } bool operator!=(const ModInt &a) const { return (x != a.x); } friend std::ostream &operator<<(std::ostream &os, const ModInt &a) { return os << a.x; } }; //////////////////////////////////////////////////////////////////////////////// constexpr unsigned MO = 998244353; using Mint = ModInt; template struct SegmentTreeRange { int logN, n; vector ts; SegmentTreeRange() {} explicit SegmentTreeRange(int n_) { for (logN = 0, n = 1; n < n_; ++logN, n <<= 1) {} ts.resize(n << 1); } template explicit SegmentTreeRange(const vector &ss) { const int n_ = ss.size(); for (logN = 0, n = 1; n < n_; ++logN, n <<= 1) {} ts.resize(n << 1); for (int i = 0; i < n_; ++i) at(i) = T(ss[i]); build(); } T &at(int i) { return ts[n + i]; } void build() { for (int u = n; --u; ) merge(u); } inline void push(int u) { ts[u].push(ts[u << 1], ts[u << 1 | 1]); } inline void merge(int u) { ts[u].merge(ts[u << 1], ts[u << 1 | 1]); } // Applies T::f(args...) to [a, b). template void ch(int a, int b, F f, Args &&... args) { assert(0 <= a); assert(a <= b); assert(b <= n); if (a == b) return; a += n; b += n; for (int h = logN; h; --h) { const int aa = a >> h, bb = b >> h; if (aa == bb) { if ((aa << h) != a || (bb << h) != b) push(aa); } else { if ((aa << h) != a) push(aa); if ((bb << h) != b) push(bb); } } for (int aa = a, bb = b; aa < bb; aa >>= 1, bb >>= 1) { if (aa & 1) (ts[aa++].*f)(args...); if (bb & 1) (ts[--bb].*f)(args...); } for (int h = 1; h <= logN; ++h) { const int aa = a >> h, bb = b >> h; if (aa == bb) { if ((aa << h) != a || (bb << h) != b) merge(aa); } else { if ((aa << h) != a) merge(aa); if ((bb << h) != b) merge(bb); } } } // Calculates the product for [a, b). T get(int a, int b) { assert(0 <= a); assert(a <= b); assert(b <= n); if (a == b) return T(); a += n; b += n; for (int h = logN; h; --h) { const int aa = a >> h, bb = b >> h; if (aa == bb) { if ((aa << h) != a || (bb << h) != b) push(aa); } else { if ((aa << h) != a) push(aa); if ((bb << h) != b) push(bb); } } T prodL, prodR, t; for (int aa = a, bb = b; aa < bb; aa >>= 1, bb >>= 1) { if (aa & 1) { t.merge(prodL, ts[aa++]); prodL = t; } if (bb & 1) { t.merge(ts[--bb], prodR); prodR = t; } } t.merge(prodL, prodR); return t; } // Calculates T::f(args...) of a monoid type for [a, b). // op(-, -) should calculate the product. // e() should return the identity. template #if __cplusplus >= 201402L auto #else decltype((std::declval().*F())()) #endif get(int a, int b, Op op, E e, F f, Args &&... args) { assert(0 <= a); assert(a <= b); assert(b <= n); if (a == b) return e(); a += n; b += n; for (int h = logN; h; --h) { const int aa = a >> h, bb = b >> h; if (aa == bb) { if ((aa << h) != a || (bb << h) != b) push(aa); } else { if ((aa << h) != a) push(aa); if ((bb << h) != b) push(bb); } } auto prodL = e(), prodR = e(); for (int aa = a, bb = b; aa < bb; aa >>= 1, bb >>= 1) { if (aa & 1) prodL = op(prodL, (ts[aa++].*f)(args...)); if (bb & 1) prodR = op((ts[--bb].*f)(args...), prodR); } return op(prodL, prodR); } // Find min b s.t. T::f(args...) returns true, // when called for the partition of [a, b) from left to right. // Returns n + 1 if there is no such b. template int findRight(int a, F f, Args &&... args) { assert(0 <= a); assert(a <= n); if ((T().*f)(args...)) return a; if (a == n) return n + 1; a += n; for (int h = logN; h; --h) push(a >> h); for (; ; a >>= 1) if (a & 1) { if ((ts[a].*f)(args...)) { for (; a < n; ) { push(a); if (!(ts[a <<= 1].*f)(args...)) ++a; } return a - n + 1; } ++a; if (!(a & (a - 1))) return n + 1; } } // Find max a s.t. T::f(args...) returns true, // when called for the partition of [a, b) from right to left. // Returns -1 if there is no such a. template int findLeft(int b, F f, Args &&... args) { assert(0 <= b); assert(b <= n); if ((T().*f)(args...)) return b; if (b == 0) return -1; b += n; for (int h = logN; h; --h) push((b - 1) >> h); for (; ; b >>= 1) if ((b & 1) || b == 2) { if ((ts[b - 1].*f)(args...)) { for (; b <= n; ) { push(b - 1); if (!(ts[(b <<= 1) - 1].*f)(args...)) --b; } return b - n - 1; } --b; if (!(b & (b - 1))) return -1; } } }; //////////////////////////////////////////////////////////////////////////////// struct Node { Mint sum; Mint lz; Node() : sum(0), lz(1) {} Node(Mint val) : sum(val), lz(1) {} void push(Node &l, Node &r) { l.mul(lz); r.mul(lz); lz = 1; } void merge(const Node &l, const Node &r) { sum = l.sum + r.sum; } void mul(Mint val) { sum *= val; lz *= val; } }; int N; vector A; int main() { for (; ~scanf("%d", &N); ) { A.resize(N); for (int i = 0; i < N; ++i) { scanf("%d", &A[i]); } vector> ps(N); for (int i = 0; i < N; ++i) { ps[i] = make_pair(A[i], i); } sort(ps.begin(), ps.end()); SegmentTreeRange segL(N), segR(N); for (int i = 0; i < N; ++i) { segL.at(i) = Node(1); segR.at(i) = Node(1); } segL.build(); segR.build(); Mint ans = 0; for (const auto &p : ps) { const int i = p.second; const Mint resL = segL.get(0, i + 1).sum; const Mint resR = segR.get(i, N).sum; const Mint hereL = segL.get(i, i + 1).sum; const Mint hereR = segR.get(i, i + 1).sum; // cerr<