Submission #981973

#	Time	Username	Problem	Language	Result	Execution time	Memory
981973		vjudge1	Sequence (APIO23_sequence)	C++17	11 / 100	2088 ms	4952 KiB

sequence

#include "sequence.h"
#include <bits/stdc++.h>

#define range(it, a, b) for (ll it = a; it < b; it++)
#define all(x) begin(x), end(x)
#define ll long long
#define ull unsigned long long
#define INF64 ((ll) 1 << 62)
#define INF32 (1 << 30)
#define mset multiset
#define uset unordered_set
#define umap unordered_map 
#define pqueue priority_queue 
#define ptr(A) shared_ptr<A>

using namespace std;

const int MAX_N = 1e5;

struct BIT {
  vector<int> bit = vector<int> (MAX_N, 0);

  void update(int i, int d) {
    for ( ; i < bit.size(); i |= i + 1)
      bit[i] += d;
  }

  int sum(int i) {
    int ans = 0;
    for ( ; i >= 0; i = (i & (i + 1)) - 1)
      ans += bit[i];
    return ans;
  }

  int sum (int l, int r) {
    return sum(r) - (l ? sum(l - 1) : 0);
  }
};

int query(int i, BIT& ft, bool even) {
  int l = 1, r = MAX_N, m;
  while (l < r) {
    m = (l+r)/2;
    if (ft.sum(m) >= i)
      r = m;
    else l = m+1;
  }
  int ans = ft.sum(l, l);
  if (even && i == ft.sum(l))
    ans = max(ans, ft.sum(l+1, l+1));
  // cout << l << ' ' << ans << '\n';
  return ans;
}

int sequence(int N, vector<int> A) {
  int maxi = 0;

  for (int l = 0; l < N; l++) {
    BIT ft;
    for (int r = l; r < N; r++) {
      // cout << "** " << l << ' ' << r << '\n';
      ft.update(A[r], 1);
      int sz = r-l+1;
      int a = sz/2 + (sz & 1);
      maxi = max(maxi, query(a, ft, !(sz & 1)));
    }
  }
  return maxi;
}

Compilation message (stderr)

sequence.cpp: In member function 'void BIT::update(int, int)':
sequence.cpp:24:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |     for ( ; i < bit.size(); i |= i + 1)
      |             ~~^~~~~~~~~~~~

• 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