Submission #981187

#	Time	Username	Problem	Language	Result	Execution time	Memory
981187		math_rabbit_1028	Sequence (APIO23_sequence)	C++17	11 / 100	2097 ms	35860 KiB

sequence

#include "sequence.h"

#include <bits/stdc++.h>
using namespace std;

int n, m, ans = 0;
vector<int> arr, vec;
vector<int> pos[505050];

int sequence(int N, vector<int> A) {
    n = N;
    arr = A;
    sort(A.begin(), A.end());
    A.erase(unique(A.begin(), A.end()), A.end());
    m = A.size();
    for (int i = 0; i < n; i++) {
        arr[i] = lower_bound(A.begin(), A.end(), arr[i]) - A.begin();
    }

    for (int i = 0; i < n; i++) {
        pos[arr[i]].push_back(i);
    }
    
    for (int t = 0; t < m; t++) {
        vec.clear();
        for (int i = 0; i < n; i++) {
            if (arr[t] == arr[i]) vec.push_back(0);
            if (arr[t] > arr[i]) vec.push_back(1);
            if (arr[t] < arr[i]) vec.push_back(-1);
        }

        for (int s = 0; s < n; s++) {
            int a = 0, b = 0, c = 0;
            for (int e = s; e < n; e++) {
                int k = (e-s+1)/2;
                if (vec[e] == -1) a++;
                if (vec[e] == 0) b++;
                if (a <= k && k <= a+b-(e-s+1)%2) ans = max(ans, b);
                /*
                    -1 : a
                    0 : b
                    1 : c
                    
                    합 짝수(2k  ) => a <= n/2 <= a+b
                    합 홀수(2k+1) => a <= n/2 <= a+b-1
                */
            }
        }
    }

    return ans;
}

Compilation message (stderr)

sequence.cpp: In function 'int sequence(int, std::vector<int>)':
sequence.cpp:33:31: warning: unused variable 'c' [-Wunused-variable]
   33 |             int a = 0, b = 0, c = 0;
      |                               ^

• Subtask 1: 11 / 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