Submission #1313264

#	Time	Username	Problem	Language	Result	Execution time	Memory
1313264		huoi	Global Warming (CEOI18_glo)	C++17	100 / 100	126 ms	28616 KiB

glo

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

#define int long long
#define INF

struct FenwickTree {
    int n;
    vector<int> t;

    FenwickTree(int n) : n(n), t(n) {}

    int lsb(int x) {
        return x & -x;
    }

    void update(int p, int x) {
        while (p <= n) {
            t[p] = max(t[p], x);
            p += lsb(p);
        }
    }

    int query(int p) {
        int ans = 0;
        while (p > 0) {
            ans = max(ans, t[p]);
            p -= lsb(p);
        }
        return ans;
    }
};

void solve() {
    int n, x;
    cin >> n >> x;

    vector<int> t(n), a;
    for (int i = 0; i < n; i++) {
        cin >> t[i];
        a.push_back(t[i]);
        a.push_back(t[i] - x);
    }

    sort(a.begin(), a.end());
    a.erase(unique(a.begin(), a.end()), a.end());

    vector<pair<int, int>> v(n);
    for (int i = 0; i < n; i++) {
        v[i].first = lower_bound(a.begin(), a.end(), t[i]) - a.begin() + 1;
        v[i].second = lower_bound(a.begin(), a.end(), t[i] - x) - a.begin() + 1;
    }

    int ans = 1;
    vector<vector<int>> dp(n, vector<int>(2, 1));
    vector<FenwickTree> ft(2, FenwickTree(2 * n + 1));

    for (int i = 0; i < n; i++) {
        dp[i][0] = max(ft[0].query(v[i].first - 1), ft[1].query(v[i].first - 1)) + 1;
        dp[i][1] = ft[1].query(v[i].second - 1) + 1;
        ft[0].update(v[i].first, dp[i][0]);
        ft[1].update(v[i].second, dp[i][1]);
        ans = max(ans, max(dp[i][0], dp[i][1]));
    }

    cout << ans;
}

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    solve();
    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