Submission #1048385

#	Time	Username	Problem	Language	Result	Execution time	Memory
1048385		otarius	Global Warming (CEOI18_glo)	C++17	100 / 100	35 ms	2816 KiB

glo

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

// #pragma GCC optimize("Ofast")
// #pragma GCC optimize ("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#define ff first
#define sc second
#define pb push_back
#define ll long long
#define pll pair<ll, ll>
#define pii pair<int, int>
#define ull unsigned long long
#define all(x) (x).begin(),(x).end()

// #define int long long
// #define int unsigned long long

#define ordered_set(T) tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>
// #define ordered_multiset(T) tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>

void open_file(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

// const ll mod = 1e9 + 7;
// const ll mod = 998244353;

const ll inf = 1e9;
const ll biginf = 1e18;
const int maxN = 2 * 1e5 + 25;

void solve() {
    int n, x;
    cin >> n >> x;
    int arr[n + 1], ans = 0;
    for (int i = 1; i <= n; i++)
        cin >> arr[i];
    vector<int> vec(n + 1, inf); int pref[n + 1];
    for (int i = 1; i <= n; i++) {
        int pos = lower_bound(vec.begin(), vec.end(), arr[i]) - vec.begin();
        vec[pos] = arr[i]; pref[i] = pos + 1;
    } for (int i = 1; i <= n; i++) vec[i] = inf;
    for (int i = 1; i <= n; i++) ans = max(ans, pref[i]);
    for (int i = n; i >= 1; i--) {
        int pos = lower_bound(vec.begin(), vec.end(), x - arr[i]) - vec.begin();
        ans = max(ans, pref[i] + pos);
        pos = lower_bound(vec.begin(), vec.end(), -arr[i]) - vec.begin();
        vec[pos] = -arr[i];
    } cout << ans;
}
int32_t main() { 
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    
    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
        cout << '\n';
    }
    return 0;
}

Compilation message (stderr)

glo.cpp: In function 'void open_file(std::string)':
glo.cpp:26:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
glo.cpp:27:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• 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