| # | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 896317 | 2024-01-01T09:07:33 Z | vjudge1 | Sequence (APIO23_sequence) | C++17 | 0 ms | 0 KB |
#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 l = 0;
int r = N-1;
while (l<=r) {
int m = (l+r) >> 1;
bool flag = 0;
for (int i=1;i<=n;i++) {
int sz = poss[i].size();
for (int j=0;j+m<sz;j++) {
int smme = sme[poss[i][j+m]]-sme[poss[i][j]]+1;
int smm = sm[poss[i][j+1]]-sm[poss[i][j]];
if (smme >= (poss[i][j+m]-poss[i][j]+2)/2 &&
smm < (poss[i][j+m]-poss[i][j]+2)/2) {
flag = 1;
}
}
}
if (flag) l = m+1;
else r = m-1;
}
return r+1;
}