Submission #956979

#	Time	Username	Problem	Language	Result	Execution time	Memory
956979		Mher777	Sequence (APIO23_sequence)	C++17	0 / 100	50 ms	29524 KiB

sequence

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <iomanip>
#include <array>
#include <string>
#include <algorithm>
#include <cmath>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <bitset>
#include <list>
#include <iterator>
#include <numeric>
#include <complex>
#include <utility>
#include <random>
#include <cassert>
#include <fstream>
#include "sequence.h"
using namespace std;
mt19937 rnd(7069);
typedef int itn;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef float fl;
typedef long double ld;
using vi = vector<int>;
using vll = vector<ll>;
using mii = map<int, int>;
using mll = map<ll, ll>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
#define ff first
#define ss second
#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define mpr make_pair
#define yes cout<<"Yes\n"
#define no cout<<"No\n"
#define all(x) (x).begin(), (x).end()
const int MAX = int(2e9 + 5);
const ll MAXL = ll(1e18) + 5ll;

const int N = 500005;
int a[N], p[N], pref[N], t[N * 4];
vi g[5];
int n, m, ans = 1;

int sequence(int N, std::vector<int> A) {
    n = N;
    g[1] = { 0 };
    g[2] = { 0 };
    g[3] = { 0 };
    for (int i = 1; i <= n; ++i) {
        a[i] = A[i - 1];
        g[a[i]].pub(i);
        pref[i] = pref[i - 1];
        if (a[i] > 1) ++pref[i];
        else --pref[i];
    }
    m = (int)g[1].size() - 1;
    mii mp;
    for (int i = 1; i <= m; ++i) {
        mp[pref[g[1][i]]] = i;
    }
    for (int i = 1; i <= m; ++i) {
        ans = max(ans, mp[pref[g[1][i]] - 1] - i + 1);
    }
    swap(g[1], g[3]);
    m = (int)g[1].size() - 1;
    mp.clear();
    for (int i = 1; i <= n; ++i) {
        pref[i] = pref[i - 1];
        if (a[i] < 3) ++pref[i];
        else --pref[i];
    }
    for (int i = 1; i <= m; ++i) {
        mp[pref[g[1][i]]] = i;
    }
    for (int i = 1; i <= m; ++i) {
        ans = max(ans, mp[pref[g[1][i] - 1]] - i + 1);
    }
    m = (int)g[2].size() - 1;
    mp.clear();
    for (int i = 1; i <= n; ++i) {
        pref[i] = pref[i - 1];
        if (a[i] == 1) --pref[i];
        else if (a[i] == 3) ++pref[i];
    }
    for (int i = 1; i <= m; i += 2) {
        mp[pref[g[2][i]]] = i;
    }
    for (int i = 1; i <= m; ++i) {
        int val = pref[g[2][i]], ind = i;
        if (mp[val - 1]) ind = max(ind, mp[val - 1]);
        if (mp[val]) ind = max(ind, mp[val]);
        if (mp[val + 1]) ind = max(ind, mp[val + 1]);
        if (!(i % 2) && mp[val - 2]) ind = max(ind, mp[val - 2]);
        if (!(i % 2) && mp[val + 2]) ind = max(ind, mp[val + 2]);
        ans = max(ans, ind - i + 1);
    }
    mp.clear();
    for (int i = 2; i <= m; i += 2) {
        mp[pref[g[2][i]]] = i;
    }
    for (int i = 1; i <= m; ++i) {
        int val = pref[g[2][i]], ind = i;
        if (mp[val - 1]) ind = max(ind, mp[val - 1]);
        if (mp[val]) ind = max(ind, mp[val]);
        if (mp[val + 1]) ind = max(ind, mp[val + 1]);
        if (i % 2 && mp[val - 2]) ind = max(ind, mp[val - 2]);
        if (i % 2 && mp[val + 2]) ind = max(ind, mp[val + 2]);
        ans = max(ans, ind - i + 1);
    }
    return ans;
}

/*
7
3 2 1 3 2 3 1
*/

• 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