Submission #1215136

#	Time	Username	Problem	Language	Result	Execution time	Memory
1215136		takoshanava	Global Warming (CEOI18_glo)	C++20	100 / 100	92 ms	5008 KiB

glo

#include <bits/stdc++.h>
#define int long long
#define pb push_back
#define fs first
#define sc second
using namespace std;

const int N = 200005, INF = 1e18;
int n, x, a[N], pref[N], suf[N];

signed main() {
    cin >> n >> x;
    for(int i = 1; i <= n; i++) cin >> a[i];

    int ans = 0;
    int dp[n + 1];

    for(int i = 0; i <= n; i++) dp[i] = INF;

    for(int i = 1; i <= n; i++){
        int l = lower_bound(dp + 1, dp + 1 + n, a[i] - x) - dp;
        dp[l] = a[i] - x;
        pref[i] = l;
        ans = max(ans, l);
    }

    for(int i = 0; i <= n; i++) dp[i] = INF;

    reverse(a + 1, a + n + 1);

    for(int i = 1; i <= n; i++){
        int l = lower_bound(dp + 1, dp + 1 + n, -(a[i] - x)) - dp;
        int id = n - i + 1;
        ans = max(ans, pref[id] + l - 1);
        l = lower_bound(dp + 1, dp + n + 1, -a[i]) - dp;
        dp[l] = -a[i];
    }

    cout << ans << endl;
}

• 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