Submission #1356280

#	Time	Username	Problem	Language	Result	Execution time	Memory
1356280		kawhiet	Sequence (APIO23_sequence)	C++20	0 / 100	81 ms	31552 KiB

sequence

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

int sequence(int n, vector<int> a) {
  vector<vector<int>> pos(n + 1);
  for (int i = 0; i < n; i++) {
    pos[a[i]].push_back(i);
  }
  int ans = 0;
  for (int x = 1; x <= n; x++) {
    if (pos[x].empty()) continue;
    vector<int> s;
    int c = 1;
    for (int i = 1; i < pos[x].size(); i++) {
      if (pos[x][i] == pos[x][i - 1] + 1) {
        c++;
      } else {
        s.push_back(c);
        c = 1;
      }
    }
    s.push_back(c);
    if (s.size() == 2) {
      int t = s[0] + s[1];
      int len = pos[x].back() - pos[x][0] + 1;
      if (2 * t >= len) {
        ans = max(ans, t);
      }
    }
    ans = max(ans, ranges::max(s));
  }
  return 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