Submission #536918

#	Time	Username	Problem	Language	Result	Execution time	Memory
536918		akhan42	Bootfall (IZhO17_bootfall)	C++17	100 / 100	748 ms	1104 KiB

bootfall

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

#define F first
#define S second
#define forn(i, n) for(int i = 0; i < n; ++i)
#define forbn(i, b, n) for(int i = b; i < n; ++i)
#define sz(v) (int)v.size()
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define min3(a, b, c) min(a, min(b, c))
#define lc v << 1
#define rc (v << 1) + 1

typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef long long ll;
typedef complex<double> cd;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

template <class T> inline void mineq(T &a, T b) { a = min(a, b); }
template <class T> inline void maxeq(T &a, T b) { a = max(a, b); }


const int BASE = 500;
const int MX = BASE * BASE + 1;
using bts = bitset<MX>;


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

	vi arr(n);
	forn(i, n)
		cin >> arr[i];

	bts s;
	s[0] = 1;
	int total = 0;
	bool odd = true, even = true;
	for(int a: arr) {
		s |= s << a;
		total += a;
		if(a % 2)
			even = false;
		else
			odd = false;
	}

	if(total % 2 || s[total / 2] == 0 || (!even && !odd))
	{
		cout << 0;
		return;
	}

	vector<bool> used(501, false);

	bts ans;
	ans.flip();

	forn(i, n) {
		if(used[arr[i]]) continue;
		used[arr[i]] = true;

		bts w;
		w[0] = 1;
		forn(j, n) {
			if(i == j) continue;
			w |= w << arr[j];
		}

		int d = (total - arr[i]) / 2;

		ans &= w >> d;
	}

	ans[0] = 0;

	cout << ans.count() << '\n';
	for(int i = ans._Find_first(); i < sz(ans); i = ans._Find_next(i)) {
		cout << 2 * i - odd << ' ';
	}
}


int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);

//	freopen("triangles.in", "r", stdin);
//	freopen("triangles.out", "w", stdout);

	int t = 1;
//	cin >> t;
	while(t--) {
		solve();
	}
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 15 / 15
• Subtask 4: 16 / 16
• Subtask 5: 21 / 21
• Subtask 6: 35 / 35