#define _USE_MATH_DEFINES #include using namespace std; #define FOR(i,m,n) for(int i=(m);i<(n);++i) #define REP(i,n) FOR(i,0,n) #define ALL(v) (v).begin(),(v).end() using ll = long long; template using posteriority_queue = priority_queue, greater >; const int INF = 0x3f3f3f3f; const ll LINF = 0x3f3f3f3f3f3f3f3fLL; const double EPS = 1e-8; const int MOD = 1000000007; // const int MOD = 998244353; const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1}; const int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1}; template inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; } template inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; } template void unique(vector &a) { a.erase(unique(ALL(a)), a.end()); } struct IOSetup { IOSetup() { cin.tie(nullptr); ios_base::sync_with_stdio(false); cout << fixed << setprecision(20); } } iosetup; int mod = MOD; struct ModInt { unsigned val; ModInt(): val(0) {} ModInt(ll x) : val(x >= 0 ? x % mod : x % mod + mod) {} ModInt pow(ll exponent) { ModInt tmp = *this, res = 1; while (exponent > 0) { if (exponent & 1) res *= tmp; tmp *= tmp; exponent >>= 1; } return res; } ModInt &operator+=(const ModInt &x) { if((val += x.val) >= mod) val -= mod; return *this; } ModInt &operator-=(const ModInt &x) { if((val += mod - x.val) >= mod) val -= mod; return *this; } ModInt &operator*=(const ModInt &x) { val = static_cast(val) * x.val % mod; return *this; } ModInt &operator/=(const ModInt &x) { // assert(__gcd(static_cast(x.val), mod) == 1); unsigned a = x.val, b = mod; int u = 1, v = 0; while (b) { unsigned tmp = a / b; swap(a -= tmp * b, b); swap(u -= tmp * v, v); } return *this *= u; } bool operator==(const ModInt &x) const { return val == x.val; } bool operator!=(const ModInt &x) const { return val != x.val; } bool operator<(const ModInt &x) const { return val < x.val; } bool operator<=(const ModInt &x) const { return val <= x.val; } bool operator>(const ModInt &x) const { return val > x.val; } bool operator>=(const ModInt &x) const { return val >= x.val; } ModInt &operator++() { if (++val == mod) val = 0; return *this; } ModInt operator++(int) { ModInt res = *this; ++*this; return res; } ModInt &operator--() { val = (val == 0 ? mod : val) - 1; return *this; } ModInt operator--(int) { ModInt res = *this; --*this; return res; } ModInt operator+() const { return *this; } ModInt operator-() const { return ModInt(val ? mod - val : 0); } ModInt operator+(const ModInt &x) const { return ModInt(*this) += x; } ModInt operator-(const ModInt &x) const { return ModInt(*this) -= x; } ModInt operator*(const ModInt &x) const { return ModInt(*this) *= x; } ModInt operator/(const ModInt &x) const { return ModInt(*this) /= x; } friend ostream &operator<<(ostream &os, const ModInt &x) { return os << x.val; } friend istream &operator>>(istream &is, ModInt &x) { ll val; is >> val; x = ModInt(val); return is; } }; ModInt abs(const ModInt &x) { return x; } struct Combinatorics { int val; // "val!" and "mod" must be disjoint. vector fact, fact_inv, inv; Combinatorics(int val = 10000000) : val(val), fact(val + 1), fact_inv(val + 1), inv(val + 1) { fact[0] = 1; FOR(i, 1, val + 1) fact[i] = fact[i - 1] * i; fact_inv[val] = ModInt(1) / fact[val]; for (int i = val; i > 0; --i) fact_inv[i - 1] = fact_inv[i] * i; FOR(i, 1, val + 1) inv[i] = fact[i - 1] * fact_inv[i]; } ModInt nCk(int n, int k) { if (n < 0 || n < k || k < 0) return ModInt(0); // assert(n <= val && k <= val); return fact[n] * fact_inv[k] * fact_inv[n - k]; } ModInt nPk(int n, int k) { if (n < 0 || n < k || k < 0) return ModInt(0); // assert(n <= val); return fact[n] * fact_inv[n - k]; } ModInt nHk(int n, int k) { if (n < 0 || k < 0) return ModInt(0); return (k == 0 ? ModInt(1) : nCk(n + k - 1, k)); } }; template struct RSQ { RSQ(int sz, const Monoid UNITY = 0) : UNITY(UNITY) { init(sz); dat.assign((n << 1) - 1, UNITY); } RSQ(const vector &a, const Monoid UNITY = 0) : UNITY(UNITY) { int a_sz = a.size(); init(a_sz); dat.resize((n << 1) - 1); REP(i, a_sz) dat[n - 1 + i] = a[i]; for (int i = n - 2; i >= 0; --i) dat[i] = dat[(i << 1) + 1] + dat[(i << 1) + 2]; } void add(int node, Monoid val) { node += n - 1; dat[node] += val; while (node > 0) { node = (node - 1) >> 1; dat[node] = dat[(node << 1) + 1] + dat[(node << 1) + 2]; } } Monoid sum(int a, int b) { return sum(a, b, 0, 0, n); } Monoid operator[](const int idx) const { return dat[idx + n - 1]; } int find(int a, int b, Monoid val) { return find(a, b, val, 0, 0, n); } private: int n = 1; const Monoid UNITY; vector dat; void init(int sz) { while (n < sz) n <<= 1; } Monoid sum(int a, int b, int node, int left, int right) { if (right <= a || b <= left) return UNITY; if (a <= left && right <= b) return dat[node]; return sum(a, b, (node << 1) + 1, left, (left + right) >> 1) + sum(a, b, (node << 1) + 2, (left + right) >> 1, right); } int find(int a, int b, Monoid val, int node, int left, int right) { if (dat[node] < val || right <= a || b <= left) return -1; if (right - left == 1) return node - (n - 1); int res_l = find(a, b, val, (node << 1) + 1, left, (left + right) >> 1); if (res_l != -1) return res_l; return find(a, b, val, (node << 1) + 2, (left + right) >> 1, right); } }; template struct RMQ { RMQ(int sz, const Monoid UNITY) : UNITY(UNITY) { init(sz); dat.assign((n << 1) - 1, UNITY); } RMQ(const vector &a, const Monoid UNITY) : UNITY(UNITY) { int a_sz = a.size(); init(a_sz); dat.resize((n << 1) - 1); REP(i, a_sz) dat[n - 1 + i] = a[i]; for (int i = n - 2; i >= 0; --i) dat[i] = max(dat[(i << 1) + 1], dat[(i << 1) + 2]); } void update(int node, Monoid val) { node += n - 1; dat[node] = val; while (node > 0) { node = (node - 1) >> 1; dat[node] = max(dat[(node << 1) + 1], dat[(node << 1) + 2]); } } Monoid query(int a, int b) { return query(a, b, 0, 0, n); } int find(int a, int b, Monoid val) { return find(a, b, val, 0, 0, n); } Monoid operator[](const int idx) const { return dat[idx + n - 1]; } private: int n = 1; const Monoid UNITY; vector dat; void init(int sz) { while (n < sz) n <<= 1; } Monoid query(int a, int b, int node, int left, int right) { if (right <= a || b <= left) return UNITY; if (a <= left && right <= b) return dat[node]; return max(query(a, b, (node << 1) + 1, left, (left + right) >> 1), query(a, b, (node << 1) + 2, (left + right) >> 1, right)); } int find(int a, int b, Monoid val, int node, int left, int right) { if (dat[node] < val || right <= a || b <= left) return -1; if (right - left == 1) return node - (n - 1); int res_l = find(a, b, val, (node << 1) + 1, left, (left + right) >> 1); if (res_l != -1) return res_l; return find(a, b, val, (node << 1) + 2, (left + right) >> 1, right); } }; template vector lis(const vector &a, const T TINF) { int n = a.size(); vector check(n, TINF); vector idx(n); REP(i, n) { idx[i] = lower_bound(ALL(check), a[i]) - check.begin(); check[idx[i]] = a[i]; } int res_sz = lower_bound(ALL(check), TINF) - check.begin(); vector res(res_sz--); for (int i = n - 1; res_sz >= 0 && i >= 0; --i) { if (idx[i] == res_sz) res[res_sz--] = a[i]; } return res; } int main() { int n; cin >> n; vector a(n); REP(i, n) cin >> a[i]; int len = lis(a, INF).size(); vector idx(n); iota(ALL(idx), 0); sort(ALL(idx), [&](int l, int r) { return a[l] == a[r] ? r < l : a[l] < a[r]; }); RMQ rmq(n, -INF); REP(i, n) rmq.update(i, 0); REP(i, n) { int now = idx[i]; rmq.update(now, max(rmq.query(0, now), 0) + 1); } // REP(i, n) cout << rmq[i] << ' '; // return 0; vector > pos(len + 1); REP(i, n) pos[rmq[i]].emplace_back(i); vector > b; REP(i, len + 1) b.emplace_back(RSQ(pos[i].size())); REP(i, n) { int now = idx[i], p = lower_bound(ALL(pos[rmq[now]]), now) - pos[rmq[now]].begin(); int prev = lower_bound(ALL(pos[rmq[now] - 1]), now) - pos[rmq[now] - 1].begin(); // cout << now << ' ' << p << ' ' << prev << ' ' << rmq[now] << endl; b[rmq[now]].add(p, rmq[now] == 1 ? 1 : b[rmq[now] - 1].sum(0, prev)); } cout << b[len].sum(0, pos[len].size()) << '\n'; return 0; }