Submission #666755

#	Time	Username	Problem	Language	Result	Execution time	Memory
666755		I_love_Chou_Giang	Global Warming (CEOI18_glo)	C++14	100 / 100	72 ms	4280 KiB

glo

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

typedef long long ll;

#define vt vector
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()

#define R_EP(i, a, b, s) for (int i = (a); (s) > 0 ? i < (b) : i > (b); i += (s))
#define R_EP1(e) R_EP(i, 0, e, 1)
#define R_EP2(i, e) R_EP(i, 0, e, 1)
#define R_EP3(i, b, e) R_EP(i, b, e, 1)
#define R_EP4(i, b, e, s) R_EP(i, b, e, s)
#define GET5(a, b, c, d, e, ...) e
#define R_EPC(...) GET5(__VA_ARGS__, R_EP4, R_EP3, R_EP2, R_EP1)
#define rep(...) R_EPC(__VA_ARGS__)(__VA_ARGS__)
#define trav(x, a) for (auto x : a) 

template<typename T> inline bool umax(T&x, const T& y) { if (x >= y) return false; x = y; return true; }
template<typename T> inline bool umin(T&x, const T& y) { if (x <= y) return false; x = y; return true; }

const int MOD = int(1e9) + 7, naxm = 200000;

int n, x, a[naxm + 5];

namespace Sub2 {
  void tst() {
    int ans = 0;
    rep(i, 1, n + 1) {
      rep(j, i, n + 1) {
        rep(t, -x, x + 1) {
          vt<int> dp;
          rep(k, 1, n + 1) {
            int v = a[k] + (k >= i && k <= j ? t : 0);
            int l = lower_bound(all(dp), v) - dp.begin();
            if (l < sz(dp)) dp[l] = v;
            else dp.pb(v);
          }
          umax(ans, sz(dp));
        }
      }
    }
    cout << ans << "\n";
  }
};

namespace Sub3 {
  void tst() {
    int ans = 0;
    rep(i, 1, n + 1) {
      vt<int> dp;
      rep(j, 1, n + 1) {
        int v = a[j] + (j <= i ? -x : 0);
        int l = lower_bound(all(dp), v) - dp.begin();
        if (l < sz(dp)) dp[l] = v;
        else dp.pb(v);
      }
      umax(ans, sz(dp));
    }
    cout << ans << "\n";
  }
};

namespace Sub4 {
  void tst() {
    vt<int> dp;
    rep(i, 1, n + 1) {
      int l = lower_bound(all(dp), a[i]) - dp.begin();
      if (l < sz(dp)) dp[l] = a[i];
      else dp.pb(a[i]);
    }
    cout << sz(dp) << "\n";
  }
};

namespace Sub7 {
  const int naxm = 200000;
  int LIS_prefix[naxm + 5];
  void tst() {
    int ans = 0;
    vt<int> dp;
    rep(i, 1, n + 1) {
      int l = lower_bound(all(dp), a[i]) - dp.begin();
      LIS_prefix[i] = l + 1;
      if (l < sz(dp)) dp[l] = a[i];
      else dp.pb(a[i]);
    }
    ans = sz(dp);
    dp.clear();
    rep(i, n, 0, -1) {
      int l = lower_bound(all(dp), -a[i] + x) - dp.begin();
      umax(ans, LIS_prefix[i] + l);
      l = lower_bound(all(dp), -a[i]) - dp.begin();
      if (l < sz(dp)) dp[l] = -a[i];
      else dp.pb(-a[i]);
    }
    cout << ans << "\n";
  }
};

int main() {
  ios_base::sync_with_stdio(false), cin.tie(nullptr);

  cin >> n >> x;
  rep(i, 1, n + 1) cin >> a[i];

  if (max(n, x) <= 50) Sub2::tst();
  else if (n <= 1000) Sub3::tst();
  else if (!x) Sub4::tst();
  else Sub7::tst();

  return 0;
}

• 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