Submission #827573

#	Time	Username	Problem	Language	Result	Execution time	Memory
827573		mgl_diamond	Global Warming (CEOI18_glo)	C++17	58 / 100	57 ms	5308 KiB

glo

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ii = pair<int, int>;
 
#define foru(i, l, r) for(int i=(l); i<=(r); ++i)
#define ford(i, l, r) for(int i=(l); i>=(r); --i)
#define fore(x, v) for(auto &x : v)
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define fi first
#define se second
#define file "input"
 
void setIO(string name="") {
  ios::sync_with_stdio(0);
  cin.tie(0); cout.tie(0);
  if (fopen(file".in", "r")) {
    freopen(file".in", "r", stdin);
    freopen(file".out", "w", stdout);
  }
}

const int N = 2e5+5;
int n, x, a[N], lb[N], rb[N], dp[N];

int main() {
  setIO();
  cin >> n >> x;
  foru(i, 1, n) cin >> a[i];
  a[n+1] = (int)1e9;

  memset(dp, 0x3f, sizeof(dp));
  foru(i, 1, n) {
    int pos = 0;
    for(int z=n>>1; z>=1; z>>=1)
      while (pos+z <= n && dp[pos+z] < a[i])
        pos += z;
    dp[pos+1] = a[i];

    for(int z=n>>1; z>=1; z>>=1) 
      while (lb[i]+z <= n && dp[lb[i]+z] < a[i+1]+x)
        lb[i] += z;
  }

  memset(dp, -0x3f, sizeof(dp));
  ford(i, n, 1) {
    int pos = 0;
    for(int z=n>>1; z>=1; z>>=1)
      while (pos+z <= n && dp[pos+z] > a[i])
        pos += z;
    dp[pos+1] = a[i];
    rb[i] = pos+1;
  }

  int ans = 0;
  foru(i, 1, n) ans = max(ans, lb[i] + rb[i+1]);
  cout << ans;
}

Compilation message (stderr)

glo.cpp: In function 'void setIO(std::string)':
glo.cpp:19:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |     freopen(file".in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
glo.cpp:20:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |     freopen(file".out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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