Submission #581387

#	Time	Username	Problem	Language	Result	Execution time	Memory
581387		drdilyor	Global Warming (CEOI18_glo)	C++17	100 / 100	86 ms	7764 KiB

glo

#if defined(ONPC) && !defined(_GLIBCXX_ASSERTIONS)
    #define _GLIBCXX_ASSERTIONS
#endif
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>
#ifdef ONPC
    #include "t_debug.cpp"
#else
    #define debug(...) 42
#endif
#define allit(a) (a).begin(), (a).end()
#define sz(a) ((int) (a).size())

using namespace std;
using ll = long long;
using vi = vector<int>;
namespace pd = __gnu_pbds;
template<typename K>
using ordered_set = pd::tree<K, pd::null_type, less<int>, pd::rb_tree_tag, pd::tree_order_statistics_node_update>;
template<typename... T>
using gp_hash_table = pd::gp_hash_table<T...>;//simple using statement gives warnings

const int INF = 1e9;
const ll INFL = 1e18;
const int N = 1e5;
const int RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count();
mt19937 rng(RANDOM);

struct Fenwick {
    int n;
    vi tree;
    Fenwick(int n) : n(n), tree(n) {}
    void set_(int i, int d) {
        for (; i < n; i |= i + 1) tree[i] = max(tree[i], d);
    }
    int max_(int i) {
        i = min(i, n-1);
        int res = 0;
        for (; i >= 0; i = (i & (i+1))-1) res = max(res, tree[i]);
        return res;
    }
};

int solve() {
    int n, x; cin >> n >> x;
    vi a(n); for (auto& i : a) cin >> i;

    // compress
    vi highest(n), b(n);
    {
        vi ix(n);
        for (int i = 0; i < n; i++) ix[i] = i;
        sort(allit(ix), [&](int i, int j) { return a[i] < a[j]; });
        for (int i = 0, prev = -1, key = -1; i < n; i++) {
            if (a[ix[i]] == prev) b[ix[i]] = key;
            else {
                prev = a[ix[i]];
                b[ix[i]] = ++key;
            }
        }

        for (int i = 0; i < n; i++) {
            int l = -1, r = n;
            while (l < r - 1) {
                int mid = (l + r) / 2;
                if (a[ix[mid]] < a[ix[i]] + x) l = mid;
                else r = mid;
            }
            highest[ix[i]] = l >= 0 ? b[ix[l]] : -1;
        }
    }

    vector<vi> dp(2, vi(n));
    Fenwick tree1(n), tree2(n);

    int res = 0;
    for (int i = 0; i < n; i++) {
        dp[0][i] = tree1.max_(b[i]-1) + 1;
        dp[1][i] = max(tree1.max_(highest[i]), tree2.max_(b[i]-1)) + 1;
        tree1.set_(b[i], dp[0][i]);
        tree2.set_(b[i], dp[1][i]);
        res = max({res, dp[1][i]});
    }
    cout << res;
    return 0;
}

signed main() {
    cin.tie(0)->sync_with_stdio(0);
    int t = 1;
    //cin >> t;
    while (t-- && cin) {
        if (solve()) break;
        #ifdef ONPC
            cout << "____________________" << endl;
        #endif
    }
    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