#include "sequence.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define P pair
#define F first
#define all(v) v.begin(),v.end()
#define V vector
#define pb push_back
#define S second
const ll MOD = (ll)1e9 + 7;
struct segtree {
private:
struct node {
int mind, maxd;
};
node single(int v) {
return {v, v};
}
node neutral = {INT_MAX, INT_MIN};
node merge(node a, node b) {
return {min(a.mind, b.mind), max(a.maxd, b.maxd)};
}
node apply(node a, int v) {
return {a.mind + v, a.maxd + v};
}
void push(int x, int lx, int rx) {
if (rx - lx == 1 || operation[x] == 0) return;
int v = operation[x];
query[2 * x + 1] = apply(query[2 * x + 1], v);
query[2 * x + 2] = apply(query[2 * x + 2], v);
operation[2 * x + 1] += v;
operation[2 * x + 2] += v;
operation[x] = 0;
}
public:
int size;
V<node> query;
V<int> operation;
void init(int n) {
size = 1;
while (size < n) size *= 2;
query.assign(2 * size, neutral);
operation.assign(2 * size, 0);
}
void build(V<int> &a, int x, int lx, int rx) {
if (rx - lx == 1) {
if (lx < (int)a.size()) {
query[x] = single(a[lx]);
}
return;
}
int m = (lx + rx) / 2;
build(a, 2 * x + 1, lx, m);
build(a, 2 * x + 2, m, rx);
query[x] = merge(query[2 * x + 1], query[2 * x + 2]);
}
void build(V<int> &a) {
build(a, 0, 0, size);
}
void set(int l, int r, int v, int x, int lx, int rx) {
push(x, lx, rx);
if (lx >= r || rx <= l) return;
if (l <= lx && rx <= r) {
query[x] = apply(query[x], v);
operation[x] += v;
return;
}
int m = (lx + rx) / 2;
set(l, r, v, 2 * x + 1, lx, m);
set(l, r, v, 2 * x + 2, m, rx);
query[x] = merge(query[2 * x + 1], query[2 * x + 2]);
}
void set(int l, int r, int v) {
set(l, r, v, 0, 0, size);
}
node calc(int l, int r, int x, int lx, int rx) {
push(x, lx, rx);
if (rx <= l || lx >= r) return neutral;
if (l <= lx && rx <= r) return query[x];
int m = (lx + rx) / 2;
node a = calc(l, r, 2 * x + 1, lx, m);
node b = calc(l, r, 2 * x + 2, m, rx);
return merge(a, b);
}
int mind(int l, int r) {
return calc(l, r, 0, 0, size).mind;
}
int maxd(int l, int r) {
return calc(l, r, 0, 0, size).maxd;
}
};
bool inter(P<int, int> a, P<int, int> b) {
if (a.F > b.F) swap(a, b);
return a.S >= b.F;
}
int f(int N, V<int> A) {
V<int> a(N + 1), occ(N + 1);
V<V<int>> pos(N + 1);
set<int> st;
for (int i = 1; i <= N; i++) {
a[i] = A[i - 1];
occ[a[i]]++;
pos[a[i]].pb(i);
st.insert(a[i]);
}
V<int> d(all(st));
V<int> b = a;
sort(all(b));
int ans = max(occ[b[(N + 1) / 2]], occ[b[(N + 2) / 2]]);
V<int> vp(N + 1);
vp[0] = 0;
for (int i = 1; i <= N; i++) vp[i] = vp[i - 1] + 1;
segtree tree;
tree.init(N + 2);
tree.build(vp);
for (auto u : d) {
V<P<P<int, int>, P<int, int>>> q;
int sz = (int)pos[u].size();
for (int i = 0; i < sz; i++) {
int mnl = tree.mind(0, pos[u][i] + 1);
int mxl = tree.maxd(0, pos[u][i] + 1);
int mnr = tree.mind(pos[u][i], N + 1);
int mxr = tree.maxd(pos[u][i], N + 1);
q.pb({{mnl, mxl}, {mnr, mxr}});
}
int l = 1, r = N;
while (l <= r) {
int m = (l + r) / 2;
bool flag = false;
for (int i = 0; i + m - 1 < sz; i++) {
P<int, int> p1 = {q[i].F.F, q[i].F.S};
P<int, int> p2 = {q[i + m - 1].S.F, q[i + m - 1].S.S};
if (inter(p1, p2)) flag = true;
}
if (flag) {
ans = max(ans, m);
l = m + 1;
} else {
r = m - 1;
}
}
for (int i = 0; i < sz; i++) {
tree.set(pos[u][i], N + 1, -2);
}
q.clear();
for (int i = 0; i < sz; i++) {
int mnl = tree.mind(0, pos[u][i] + 1);
int mxl = tree.maxd(0, pos[u][i] + 1);
int mnr = tree.mind(pos[u][i], N + 1);
int mxr = tree.maxd(pos[u][i], N + 1);
q.pb({{mnl, mxl}, {mnr, mxr}});
}
l = 1, r = N;
while (l <= r) {
int m = (l + r) / 2;
bool flag = false;
for (int i = 0; i + m - 1 < sz; i++) {
P<int, int> p1 = {q[i].F.F, q[i].F.S};
P<int, int> p2 = {q[i + m - 1].S.F, q[i + m - 1].S.S};
if (inter(p1, p2)) flag = true;
}
if (flag) {
ans = max(ans, m);
l = m + 1;
} else {
r = m - 1;
}
}
}
return ans;
}
int sequence(int N, std::vector<int> A) {
return f(N, A);
}
