제출 #982051

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
982051		vjudge1	서열 (APIO23_sequence)	C++17	0 / 100	2051 ms	373408 KiB

sequence

#include "sequence.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector <ll>;
using vi = vector <int>;
using ii = pair <ll, ll>;
using vii = vector <ii>;

struct MedianDS {
    multiset <ll, greater <ll> > st1; // big to small (mid...0)
    multiset <ll> st2; // small to big (mid...n)
    vll freq;

    MedianDS (ll n): freq(n, 0) {}

    void stabilize () {
        while (st2.size() > st1.size()) {
            st1.insert(*st2.begin());
            st2.erase(st2.begin());
        }
        while (st1.size() > st2.size()) {
            st2.insert(*st1.begin());
            st1.erase(st1.begin());
        }
    }

    void insert (ll x) {
        ll mid = (st2.size() ? *st2.begin() : 0);
        if (x >= mid) st2.insert(x);
        else st1.insert(x);
        freq[x]++;
        stabilize();
    }

    void erase (ll x) {
        ll mid = (st2.size() ? *st2.begin() : 0);
        if (x >= mid) st2.erase(st2.find(x));
        else st1.erase(st1.find(x));
        freq[x]--;
        stabilize();
    }

    ll query () {
        if (st1.size() == st2.size()) { // two medians
            ll med1 = *st1.begin();
            ll med2 = *st2.begin();
            return max(freq[med1], freq[med2]);
        } else { // one median
            assert(st2.size() > st1.size());
            ll med = *st2.begin();
            return freq[med];
        }
    }
};

int sequence (int n, vi ve) {
    for (int &i : ve) i--;
    ll ans = 1;
    deque <ll> dqs[n];
    for (ll i = 0; i < n; i++) {
        dqs[ve[i]].push_back(i);
    }
    for (ll i = 0; i < n; i++) {
        deque <ll> &dq = dqs[i];
        if (dq.size() < 2) continue;
        MedianDS ds(n);
        ll l = dq.front(), r = dq.back();
        for (ll j = l; j <= r; j++) {
            ds.insert(ve[j]);
        }
        ans = max(ans, ds.query());
        while (dq.size() >= 2) {
            ll disF = dq[1]-dq[0];
            ll disB = dq[dq.size()-1]-dq[dq.size()-2];
            if (disF > disB) {
                dq.pop_front();
                while (l++ < dq.front()) ds.erase(ve[l-1]);
            } else {
                dq.pop_back();
                while (r-- > dq.back()) ds.erase(ve[r+1]);
            }
            ans = max(ans, ds.query());
        }
    }
    return int(ans);
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 17
• Subtask 3: 0 / 7
• Subtask 4: 0 / 12
• Subtask 5: 0 / 13
• Subtask 6: 0 / 22
• Subtask 7: 0 / 18