Submission #486691

#	Time	Username	Problem	Language	Result	Execution time	Memory
486691		ez_ioi	Longest beautiful sequence (IZhO17_subsequence)	C++17	100 / 100	4347 ms	184596 KiB

subsequence

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

const int mxN = 3e6 + 5, mod = 1e9 + 7, LOG = 20;

int n, a[mxN], k[mxN], dp[mxN], p[mxN];
pair <int, int> d[mxN];
pair <int, int> st[2005][2005][21];
int mask1[mxN], mask2[mxN];
int bruh[mxN];

int main() {
	ios :: sync_with_stdio(false), cin.tie(nullptr);
	cin >> n;
	for (int i = 1; i <= n; ++i) cin >> a[i];
	for (int i = 1; i <= n; ++i) cin >> k[i];
	if (n <= 5000) {
		pair <int, int> ans = {0, 0};
		for (int i = 1; i <= n; ++i) {
			dp[i] = 1;
			for (int j = i - 1; j > 0; j--) {
				if (__builtin_popcount((a[i] & a[j])) == k[i]) {
					if (dp[j] + 1 > dp[i]) {
						dp[i] = dp[j] + 1;
						p[i] = j;
					}
				}
			}
			ans = max(ans, {dp[i], i});
		}
		cout << ans.first << '\n';
		int now = ans.second;
		vector <int> seq;
		while (now) { seq.push_back(now); now = p[now]; }
		reverse(seq.begin(), seq.end());
		for (auto x : seq) cout << x << ' ';
		return 0;
	}
	vector <int> f, s;
	for (int i = 1; i <= n; ++i) {
		for (int j = 0; j < 10; ++j) {
			if ((a[i] >> j) & 1) mask1[i] += (1 << j);
		}
		for (int j = 10; j < 20; ++j) {
			if ((a[i] >> j) & 1) mask2[i] += (1 << (j - 10));
		}
		f.push_back(mask1[i]); s.push_back(mask2[i]);
	}
	sort(f.begin(), f.end());
	f.erase(unique(f.begin(), f.end()), f.end());
	sort(s.begin(), s.end());
	s.erase(unique(s.begin(), s.end()), s.end());
	assert(min((int)f.size(), (int)s.size()) <= (1 << 10));
	pair <int, int> ans = {0, 0};
	for (int i = 0; i < (1 << 20); ++i) bruh[i] = __builtin_popcount(i);
	for (int i = 1; i <= n; ++i) {
		dp[i] = 1;
		{ // get
			for (auto mask : f) {
				int x = bruh[mask1[i] & mask];
				if (x > k[i]) continue;
				pair <int, int> y = st[mask][mask2[i]][k[i] - x];
				if (y.first + 1 > dp[i]) {
					p[i] = y.second;
					dp[i] = y.first + 1;
				}
			}
		}
		{ // upd
			for (auto mask : s) {
				int x = bruh[mask & mask2[i]];
				st[mask1[i]][mask][x] = max(st[mask1[i]][mask][x], {dp[i], i});
			}
		}
		ans = max(ans, {dp[i], i});
	}
	int now = ans.second;
	vector <int> seq;
	while (now > 0) {
		seq.push_back(now);
		now = p[now];
	}
	reverse(seq.begin(), seq.end());
	cout << (int)seq.size() << '\n';
	for (auto x : seq) cout << x << ' ';
	return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 16 / 16
• Subtask 3: 17 / 17
• Subtask 4: 60 / 60