#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
#include "sequence.h"
using namespace std;const int LIM = 5e5+1;
vector<int> bit(LIM,0);
int n;
void add(int p,int v) {
for (int i=p;i<=n;i+=i&-i) bit[i]+=v;
}
int get(int p) {
int ans = 0;
for (int i=p;i>0;i-=i&-i) ans+=bit[i];
return ans;
}
int sequence(int N, std::vector<int> A) {
n = N;
vector<int> sme(N+1);
vector<int> sm(N+1);
for (int i=1;i<=N;i++) {
add(A[i-1],1);
sme[i] = get(A[i-1]);
sm[i] = get(A[i-1]-1);
}
vector<int> poss[N+1];
for (int i=1;i<=n;i++) poss[A[i-1]].push_back(i);
int ans = 1;
for (int i=1;i<=n;i++) {
int sz = poss[i].size();
for (int j=0;j<sz;j++) {
for (int j2=j+1;j2<sz;j2++) {
int smme = sme[poss[i][j2]]-sme[poss[i][j]]+1;
int smm = sm[poss[i][j2]]-sm[poss[i][j]];
if (smme >= (poss[i][j2]-poss[i][j]+2)/2 &&
smm < (poss[i][j2]-poss[i][j]+2)/2) ans = max(ans,j2-j+1);
}
}
}
return ans;
}
