Submission #752896

#	Time	Username	Problem	Language	Result	Execution time	Memory
752896		I_love_Hoang_Yen	Sequence (APIO23_sequence)	C++17	28 / 100	676 ms	4184 KiB

sequence

#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;
}

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