Submission #544471

#	Time	Username	Problem	Language	Result	Execution time	Memory
544471		cig32	Global Warming (CEOI18_glo)	C++17	100 / 100	79 ms	10104 KiB

glo

#include "bits/stdc++.h"
using namespace std;
const int MAXN = 2e5 + 10;
const int MOD = 1e9 + 7;
#define int long long
#define ll __int128
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
  int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
ll read() { // read int128
  int x; cin >> x; return (ll)x;
}
long long bm(long long b, long long p) {
  if(p==0) return 1 % MOD;
  long long r = bm(b, p >> 1);
  if(p&1) return (((r*r) % MOD) * b) % MOD;
  return (r*r) % MOD;
}
long long inv(long long b) { 
  return bm(b, MOD-2);
}
long long f[MAXN];
long long nCr(int n, int r) { 
  long long ans = f[n]; ans *= inv(f[r]); ans %= MOD;
  ans *= inv(f[n-r]); ans %= MOD; return ans;
}
void precomp() { 
  for(int i=0; i<MAXN; i++) f[i] = (i == 0 ? 1 % MOD : (f[i-1] * i) % MOD);
}
void solve(int tc) {
  int n, x;
  cin >> n >> x;
  int t[n+1];
  for(int i=1; i<=n; i++) cin >> t[i];
  int bucket_pref[n+1], bucket_suf[n+1];
  for(int i=0; i<=n; i++) {
    bucket_pref[i] = 2e9;
    bucket_suf[i] = 2e9;
  }
  int ans = 0;
  int pref_dp[n+1];
  for(int i=1; i<=n; i++) {
    auto it = lower_bound(bucket_pref + 1, bucket_pref + n + 1, t[i] - x);
    int d = distance(bucket_pref, it);
    bucket_pref[d] = t[i] - x;
    pref_dp[i] = d;
    ans = max(ans, d);
  }
  //cout << ans << " ";
  for(int i=n; i>=1; i--) {
    auto it = lower_bound(bucket_suf + 1, bucket_suf + n + 1, -t[i]);
    int d = distance(bucket_suf, it);
    bucket_suf[d] = -t[i];
    if(i > 1) {
      //if(i == 5) for(int j=1; j<=n; j++)cout << bucket_suf[j]<<" \n"[j==n];
      auto it2 = lower_bound(bucket_suf, bucket_suf + n + 1, -(t[i-1] - x));
      int d2 = distance(bucket_suf, it2);
      //if(i == 5) cout << "gay " << d2 << "\n";
      ans = max(ans, pref_dp[i-1] + d2 - 1);
    }
  }
  cout << ans << "\n";
}
int32_t main(){
  precomp();
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; //cin >> t;
  for(int i=1; i<=t; i++) solve(i);
} 

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