Submission #993476

#	Time	Username	Problem	Language	Result	Execution time	Memory
993476		messiuuuuu	Global Warming (CEOI18_glo)	C++14	100 / 100	75 ms	5484 KiB

glo

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

int temps[200005];
int pref_longest[200005];

int main() {
	int n;
	int x;
	cin >> n >> x;
	for (int i = 0; i < n; i++) { cin >> temps[i]; }

	vector<int> dp(n, INT_MAX);
	int longest = 0;
	// longest increasing subsequence ending at i
	for (int i = 0; i < n; i++) {
		int j = lower_bound(dp.begin(), dp.end(), temps[i]) - dp.begin();
		dp[j] = temps[i];
		pref_longest[i] = j + 1;
		longest = max(longest, pref_longest[i]);
	}

	dp = vector<int>(n, INT_MAX);
	// longest decreasing subsequence ending at i of reverse
	// = longest increasing subsequence starting at i
	for (int i = n - 1; i >= 0; i--) {
		int pos = lower_bound(dp.begin(), dp.end(), -temps[i] + x) - dp.begin();
		longest = max(longest, pref_longest[i] + pos);

		int insert_pos =
		    lower_bound(dp.begin(), dp.end(), -temps[i]) - dp.begin();
		dp[insert_pos] = -temps[i];
	}
	cout << longest << 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