#include "bits/stdc++.h" #pragma warning(disable:4996) using namespace std; #define int long long #define rep(i,n) for(int i=0;i P; const long long mod = 1000000007; const long long inf = 1ll << 61; struct RMQ { int n; vectornode, node2; void init(int N) { n = 1; while (n < N)n *= 2; node.resize(2 * n, inf); node2.resize(2 * n, -inf); } void update(int x, int a) { x += n - 1; node[x] = a; node2[x] = a; while (x > 0) { x = (x - 1) / 2; node[x] = min(node[x * 2 + 1], node[x * 2 + 2]); node2[x] = max(node2[x * 2 + 1], node2[x * 2 + 2]); } } int query(int a, int b, int k, int l, int r) { if (r <= a || b <= l)return inf; if (a <= l&&r <= b)return node[k]; int vl = query(a, b, k * 2 + 1, l, (l + r) / 2); int vr = query(a, b, k * 2 + 2, (l + r) / 2, r); return min(vl, vr); } int query2(int a, int b, int k, int l, int r) { if (r <= a || b <= l)return -inf; if (a <= l&&r <= b)return node2[k]; int vl = query2(a, b, k * 2 + 1, l, (l + r) / 2); int vr = query2(a, b, k * 2 + 2, (l + r) / 2, r); return max(vl, vr); } int getmin(int a, int b) { return query(a, b, 0, 0, n); } int getmax(int a, int b) { return query2(a, b, 0, 0, n); } }; struct BIT { int bit[100006]; int N; void init(int n) { N = n; for (int i = 0; i <= N; i++)bit[i] = 0; } int sum(int i) { int s = 0; while (i > 0) { s += bit[i]; i -= i&-i; } return s; } void add(int i, int x) { while (i <= N) { bit[i] += x; i += i&-i; } } }; int p[100005]; int n; RMQ seg; BIT bi; vector

LS, RS, v; int sis(int l, int r, int base) {//初項がbaseのときのISを計算 int res = 0, mn = base; for (int i = l; i <= r; i++) { if (mn <= p[i]) { mn = p[i]; res++; } } return res; } void input() { cin >> n; rep(i, n)cin >> p[i]; seg.init(n); rep(i, n)seg.update(i, p[i]); bi.init(n + 1); } int sqrtdc(vector

S) { int sqrtN = sqrt(n); vector

iss[400]; vectormaxnum; int K = (n + sqrtN - 1) / sqrtN; rep(i, K) { int l1 = i*sqrtN, r1 = min(l1 + sqrtN - 1, n - 1); for (int j = l1; j <= r1; j++) { iss[i].push_back(P(p[j], sis(l1, r1, p[j]))); } iss[i].push_back(P(inf, 0)); sort(iss[i].begin(), iss[i].end()); } int ans = 0; rep(i, n) { if (S[i].first > S[i].second)continue; int L = S[i].first, R = S[i].second + 1; int mn = 0; for (int k = 0; k < K; k++) { int l = k*sqrtN, r = (k + 1)*sqrtN; if (r <= L || R <= l)continue; if (L <= l&&r <= R) { auto p2 = *lower_bound(iss[k].begin(), iss[k].end(), P(mn, -1)); if (p2.first != inf) { ans += p2.second; mn = seg.getmax(l, r); } } else { for (int j = max(l, L); j < min(R, r); j++) { if (mn < p[j]) { ans++; mn = p[j]; } } } } } return ans; } int honsitu() { //区間に分ける rep(i, n)v.push_back(P(p[i], i)); sort(v.begin(), v.end()); rep(i, n) { int s = bi.sum(v[i].second); int lb = v[i].second, ub = n + 1; while (ub - lb > 1) { int mi = (ub + lb) / 2; if (bi.sum(mi) > s)ub = mi; else lb = mi; } RS.push_back(P(v[i].second + 1, lb - 1)); bi.add(v[i].second + 1, 1); } int ans = sqrtdc(RS); reverse(p, p + n); bi.init(n + 1); seg.init(n); rep(i, n)seg.update(i, p[i]); rep(i, n) { v[i].second = n - 1 - v[i].second; int s = bi.sum(v[i].second); int lb = v[i].second, ub = n + 1; while (ub - lb > 1) { int mi = (ub + lb) / 2; if (bi.sum(mi) > s)ub = mi; else lb = mi; } LS.push_back(P(v[i].second + 1, lb - 1)); bi.add(v[i].second + 1, 1); } ans += sqrtdc(LS); return ans; } signed main() { input(); cout << honsitu() << endl; }