Submission #978801

#	Time	Username	Problem	Language	Result	Execution time	Memory
978801		duckindog	Global Warming (CEOI18_glo)	C++17	10 / 100	281 ms	7780 KiB

glo

#include <bits/stdc++.h>

using namespace std;

const int N = 200'000 + 10;
int n, x;
int a[N];

vector<int> rrh;

int f[N << 2];
void update(int s, int l, int r, int i, int value) { 
  if (i < l || i > r) return;
  if (l == r) { 
    f[s] = value;
    return;
  }
  int mid = l + r >> 1;
  update(s << 1, l, mid, i, value); update(s << 1 | 1, mid + 1, r, i, value);
  f[s] = max(f[s << 1], f[s << 1 | 1]);
}
int query(int s, int l, int r, int u, int v) { 
  if (v < l || u > r) return 0;
  if (u <= l && r <= v) return f[s];
  int mid = l + r >> 1;
  return max(query(s << 1, l, mid, u, v), query(s << 1 | 1, mid + 1, r, u, v));
}

int bwd[N];

int32_t main() { 
  cin.tie(0)->sync_with_stdio(0);

  cin >> n >> x;
  for (int i = 1; i <= n; ++i) cin >> a[i];

  rrh = vector<int> (a + 1, a + n + 1);
  sort(rrh.begin(), rrh.end());
  rrh.resize(unique(rrh.begin(), rrh.end()) - rrh.begin());

  for (int i = n; i >= 1; --i) { 
    int l = lower_bound(rrh.begin(), rrh.end(), a[i]) - rrh.begin() + 1;
    bwd[i] = query(1, 1, rrh.size(), l + 1, rrh.size()) + 1;
    update(1, 1, rrh.size(), l, bwd[i]);
  }

  memset(f, 0, sizeof f);
  int answer = 0;
  for (int i = 1; i <= n; ++i) { 
    int it = upper_bound(rrh.begin(), rrh.end(), x - a[i]) - rrh.begin();
    answer = max(answer, bwd[i] + query(1, 1, rrh.size(), 1, it));
    
    int r = lower_bound(rrh.begin(), rrh.end(), a[i]) - rrh.begin() + 1;
    update(1, 1, rrh.size(), r, query(1, 1, rrh.size(), 1, r) + 1);
  }

  cout << answer << "\n";
}

Compilation message (stderr)

glo.cpp: In function 'void update(int, int, int, int, int)':
glo.cpp:18:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   18 |   int mid = l + r >> 1;
      |             ~~^~~
glo.cpp: In function 'int query(int, int, int, int, int)':
glo.cpp:25:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   25 |   int mid = l + r >> 1;
      |             ~~^~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 13
• Subtask 4: 10 / 10
• Subtask 5: 0 / 20
• Subtask 6: 0 / 17
• Subtask 7: 0 / 25