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Submission #752910

# Submission time Handle Problem Language Result Execution time Memory
752910 2023-06-04T08:51:49 Z I_love_Hoang_Yen Sequence (APIO23_sequence) C++17
35 / 100
 684 ms 31688 KB 
#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;
}

bool is_sub_3(const std::vector<int> a) {
    auto mit = max_element(a.begin(), a.end());
    return std::is_sorted(a.begin(), mit)
        && std::is_sorted(mit, a.end(), std::greater<int>());
}

int len(const std::pair<int,int>& p) {
    return p.second - p.first + 1;
}
bool can_be_median(int cnt_less, int cnt_equal, int cnt_greater) {
    if (cnt_equal >= cnt_greater) return true;
    else return cnt_equal + cnt_less >= cnt_greater;
}

int sub3(const vector<int>& a) {
    int n = SZ(a);
    unordered_map<int, vector<pair<int,int>>> pos;
    int l = 0;
    while (l < n) {
        int r = l;
        while (r < n && a[l] == a[r]) ++r;
        pos[a[l]].emplace_back(l, r-1);
        l = r;
    }
    int res = 0;
    for (const auto& [val, lrs] : pos) {
        // only 1 segment
        for (const auto& lr : lrs) res = max(res, len(lr));

        // 2 segments
        if (SZ(lrs) < 2) continue;
        assert(SZ(lrs) == 2);
        int cnt_equal = len(lrs[0]) + len(lrs[1]);
        int cnt_greater = len({lrs[0].second + 1, lrs[1].first - 1});
        int cnt_less = len({0, lrs[0].first - 1}) + len({lrs[1].second + 1, n-1});
        if (can_be_median(cnt_less, cnt_equal, cnt_greater)) {
            res = max(res, cnt_equal);
        }
    }
    return res;
}

int sequence(int n, std::vector<int> a) {
    if (is_sub_3(a)) return sub3(a);
    if (n <= 2000) return sub2(a);
    return 0;
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 2 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 2 ms 212 KB Output is correct
12 Correct 2 ms 212 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 2 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 2 ms 212 KB Output is correct
12 Correct 2 ms 212 KB Output is correct
13 Correct 681 ms 468 KB Output is correct
14 Correct 664 ms 472 KB Output is correct
15 Correct 454 ms 392 KB Output is correct
16 Correct 461 ms 384 KB Output is correct
17 Correct 431 ms 384 KB Output is correct
18 Correct 1 ms 468 KB Output is correct
19 Correct 632 ms 548 KB Output is correct
20 Correct 629 ms 436 KB Output is correct
21 Correct 633 ms 444 KB Output is correct
22 Correct 684 ms 444 KB Output is correct

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 150 ms 31656 KB Output is correct
3 Correct 178 ms 31688 KB Output is correct
4 Correct 42 ms 6100 KB Output is correct
5 Correct 171 ms 29216 KB Output is correct
6 Correct 152 ms 29144 KB Output is correct
7 Correct 41 ms 6108 KB Output is correct
8 Correct 42 ms 6092 KB Output is correct
9 Correct 41 ms 6104 KB Output is correct

Subtask #4
0.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Incorrect 42 ms 6088 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #5
0.0 / 13.0

# Verdict Execution time Memory Grader output
1 Incorrect 52 ms 6088 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 2 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 2 ms 212 KB Output is correct
12 Correct 2 ms 212 KB Output is correct
13 Correct 681 ms 468 KB Output is correct
14 Correct 664 ms 472 KB Output is correct
15 Correct 454 ms 392 KB Output is correct
16 Correct 461 ms 384 KB Output is correct
17 Correct 431 ms 384 KB Output is correct
18 Correct 1 ms 468 KB Output is correct
19 Correct 632 ms 548 KB Output is correct
20 Correct 629 ms 436 KB Output is correct
21 Correct 633 ms 444 KB Output is correct
22 Correct 684 ms 444 KB Output is correct
23 Incorrect 9 ms 1236 KB Output isn't correct
24 Halted 0 ms 0 KB -

Subtask #7
0.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 2 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 2 ms 212 KB Output is correct
12 Correct 2 ms 212 KB Output is correct
13 Correct 681 ms 468 KB Output is correct
14 Correct 664 ms 472 KB Output is correct
15 Correct 454 ms 392 KB Output is correct
16 Correct 461 ms 384 KB Output is correct
17 Correct 431 ms 384 KB Output is correct
18 Correct 1 ms 468 KB Output is correct
19 Correct 632 ms 548 KB Output is correct
20 Correct 629 ms 436 KB Output is correct
21 Correct 633 ms 444 KB Output is correct
22 Correct 684 ms 444 KB Output is correct
23 Correct 150 ms 31656 KB Output is correct
24 Correct 178 ms 31688 KB Output is correct
25 Correct 42 ms 6100 KB Output is correct
26 Correct 171 ms 29216 KB Output is correct
27 Correct 152 ms 29144 KB Output is correct
28 Correct 41 ms 6108 KB Output is correct
29 Correct 42 ms 6092 KB Output is correct
30 Correct 41 ms 6104 KB Output is correct
31 Incorrect 42 ms 6088 KB Output isn't correct
32 Halted 0 ms 0 KB -