Submission #536195

#	Time	Username	Problem	Language	Result	Execution time	Memory
536195		akhan42	Bootfall (IZhO17_bootfall)	C++17	44 / 100	1022 ms	2640 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>;


int last_bit(bts& a) {
	int i = a._Find_first();
	while(a._Find_next(i) != sz(a))
		i = a._Find_next(i);
	return i;
}


int pr2 = 479001599;


int add(int a, int b, int mod) {
	return ((a + b) % mod + mod) % mod;
}



bts divide(vi pol2, int d) {
	bts res;

	for(int i = 0; i + d < MX; i++) {
		if(pol2[i] != 0) {
			pol2[i + d] = add(pol2[i + d], -pol2[i], pr2);
			res[i] = 1;
		}
	}

	return res;
}


void solve() {
	int n;
	cin >> n;
	vi arr(n);
	forn(i, n)
	cin >> arr[i];
	sort(all(arr));

	vi pol2(MX, 0);
	pol2[0] = 1;
	for(int a: arr) {
		for(int i = MX - a - 1; i >= 0; i--) {
			pol2[i + a] = add(pol2[i + a], pol2[i], pr2);
		}
	}


	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;
	}

	bts ans;
	ans.flip();
	forn(i, n) {
		bts c = divide(pol2, arr[i]);

		int d = (total - arr[i] - (odd ? 1 : 0)) / 2;

		ans &= c >> d;
	}

	vi vans;
	forbn(i, 1, MX) {
		if(ans[i]) {
			vans.pb(2 * i - (odd ? 1 : 0));
		}
	}

	cout << sz(vans) << '\n';
	for(int el: vans)
		cout << el << ' ';
}


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();
	}
}

Compilation message (stderr)

bootfall.cpp: In function 'int last_bit(bts&)':
bootfall.cpp:40:24: warning: comparison of integer expressions of different signedness: 'std::size_t' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   40 |  while(a._Find_next(i) != sz(a))
      |                        ^

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 15 / 15
• Subtask 4: 16 / 16
• Subtask 5: 0 / 21
• Subtask 6: 0 / 35