#include #include #include using namespace std; typedef unsigned long long _ulong; typedef long long int lint; typedef long double ld; typedef pair plint; typedef pair pld; #define ALL(x) (x).begin(), (x).end() #define SZ(x) ((lint)(x).size()) #define FOR(i, begin, end) for(lint i=(begin),i##_end_=(end);i=i##_begin_;--i) #define REP(i, n) FOR(i,0,n) #define IREP(i, n) IFOR(i,0,n) #define endk '\n' #define fi first #define se second struct fast_ios { fast_ios() { cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_; template auto add = [](T a, T b) -> T { return a + b; }; template auto f_max = [](T a, T b) -> T { return max(a, b); }; template auto f_min = [](T a, T b) -> T { return min(a, b); }; template using V = vector; using Vl = V; using VVl = V; template< typename T > ostream& operator<<(ostream& os, const vector< T >& v) { for (int i = 0; i < (int)v.size(); i++) os << v[i] << (i + 1 != v.size() ? " " : ""); return os; } template< typename T >istream& operator>>(istream& is, vector< T >& v) { for (T& in : v) is >> in; return is; } template bool chmax(T& a, const T& b) { if (a < b) { a = b; return 1; } return 0; } template bool chmin(T& a, const T& b) { if (b < a) { a = b; return 1; } return 0; } lint gcd(lint a, lint b) { if (b == 0) return a; else return gcd(b, a % b); } lint ceil(lint a, lint b) { return (a + b - 1) / b; } lint digit(lint a) { return (lint)log10(a); } lint e_dist(plint a, plint b) { return abs(a.fi - b.fi) * abs(a.fi - b.fi) + abs(a.se - b.se) * abs(a.se - b.se); } lint m_dist(plint a, plint b) { return abs(a.fi - b.fi) + abs(a.se - b.se); } bool check_overflow(lint a, lint b, lint limit) { return a > limit / b; } // a * b > c => true void Worshall_Floyd(VVl& g) { REP(k, SZ(g)) REP(i, SZ(g)) REP(j, SZ(g)) chmin(g[i][j], g[i][k] + g[k][j]); } const lint MOD1000000007 = 1000000007, MOD998244353 = 998244353, INF = 5e18; lint dx[8] = { 1, 0, -1, 0, 1, -1, 1, -1 }, dy[8] = { 0, 1, 0, -1, -1, -1, 1, 1 }; bool YN(bool flag) { cout << (flag ? "YES" : "NO") << endk; return flag; } bool yn(bool flag) { cout << (flag ? "Yes" : "No") << endk; return flag; } struct Edge { lint from, to; lint cost; Edge() { } Edge(lint u, lint v, lint c) { cost = c; from = u; to = v; } bool operator<(const Edge& e) const { return cost < e.cost; } }; struct WeightedEdge { lint to; lint cost; WeightedEdge(lint v, lint c = 1) { to = v; cost = c; } bool operator<(const WeightedEdge& e) const { return cost < e.cost; } }; using WeightedGraph = V>; typedef pair tlint; typedef pair qlint; typedef pair valchar; template< typename Monoid > struct SegmentTree { using F = function< Monoid(Monoid, Monoid) >; int sz; vector< Monoid > seg; const F f; const Monoid M1; SegmentTree(int n, const F f, const Monoid& M1) : f(f), M1(M1) { sz = 1; while (sz < n) sz <<= 1; seg.assign(2 * sz, M1); } void set(int k, const Monoid& x) { seg[k + sz] = x; } void build() { for (int k = sz - 1; k > 0; k--) { seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]); } } void update(int k, const Monoid& x) { k += sz; seg[k] = x; while (k >>= 1) { seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]); } } Monoid query(int a, int b) { Monoid L = M1, R = M1; for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) { if (a & 1) L = f(L, seg[a++]); if (b & 1) R = f(seg[--b], R); } return f(L, R); } Monoid operator[](const int& k) const { return seg[k + sz]; } template< typename C > int find_subtree(int a, const C& check, Monoid& M, bool type) { while (a < sz) { Monoid nxt = type ? f(seg[2 * a + type], M) : f(M, seg[2 * a + type]); if (check(nxt)) a = 2 * a + type; else M = nxt, a = 2 * a + 1 - type; } return a - sz; } template< typename C > int find_first(int a, const C& check) { Monoid L = M1; if (a <= 0) { if (check(f(L, seg[1]))) return find_subtree(1, check, L, false); return -1; } int b = sz; for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) { if (a & 1) { Monoid nxt = f(L, seg[a]); if (check(nxt)) return find_subtree(a, check, L, false); L = nxt; ++a; } } return -1; } template< typename C > int find_last(int b, const C& check) { Monoid R = M1; if (b >= sz) { if (check(f(seg[1], R))) return find_subtree(1, check, R, true); return -1; } int a = sz; for (b += sz; a < b; a >>= 1, b >>= 1) { if (b & 1) { Monoid nxt = f(seg[--b], R); if (check(nxt)) return find_subtree(b, check, R, true); R = nxt; } } return -1; } }; lint N; int main() { cin >> N; Vl arr(N); cin >> arr; SegmentTree mint(N, f_min, INF), maxt(N, f_max, 0); REP(i, N) { mint.set(i, arr[i]); maxt.set(i, arr[i]); } mint.build(); maxt.build(); lint idx = 0; auto check = [&](lint l, lint r) { lint maxv = maxt.query(l, r + 1); lint minv = mint.query(l, r + 1); lint minp = mint.find_first(l, [&](lint v) { return v <= minv; }); mint.update(minp, INF); lint _minv = mint.query(l, r + 1); mint.update(minp, minv); return maxv <= minv + _minv; }; lint ans = 0; REP(i, N - 1) { chmax(idx, i + 1); while (idx < N && check(i, idx)) { idx++; } ans += idx - i - 1; } cout << ans << endk; }