#include "sequence.h"
#include <bits/stdc++.h>
#define SZ(s) ((int) ((s).size()))
using namespace std;
vector<int> medians(const vector<int> values) {
int n = SZ(values);
assert(n > 0);
if (n % 2 == 0) {
return {values[n/2 - 1], values[n / 2]};
} else {
return {values[n/2]};
}
}
int sub1(const vector<int>& a) {
int n = SZ(a);
int res = 0;
for (int l = 0; l < n; ++l) {
for (int r = l; r < n; ++r) {
vector<int> b(a.begin() + l, a.begin() + r + 1);
unordered_map<int, int> cnt;
for (int val : b) cnt[val] += 1;
sort(b.begin(), b.end());
auto meds = medians(b);
for (int med : meds) {
res = max(res, cnt[med]);
}
}
}
return res;
}
#include <ext/pb_ds/assoc_container.hpp> // Common file
#include <ext/pb_ds/tree_policy.hpp> // Including tree_order_statistics_node_update
using namespace __gnu_pbds;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
using namespace __gnu_pbds;
int sub2(const vector<int>& a) {
int n = SZ(a);
int res = 0;
for (int l = 0; l < n; ++l) {
unordered_map<int, int> cnt;
ordered_set values;
for (int r = l; r < n; ++r) {
cnt[a[r]]++;
values.insert(a[r]);
int k = SZ(values);
if (k % 2 == 0) {
res = max(res, cnt[*values.find_by_order(k / 2 - 1)]);
res = max(res, cnt[*values.find_by_order(k / 2)]);
} else {
res = max(res, cnt[*values.find_by_order(k / 2)]);
}
}
}
return res;
}
int sequence(int n, std::vector<int> a) {
if (n <= 2000) return sub2(a);
return 0;
}
