Submission #536220

#	Time	Username	Problem	Language	Result	Execution time	Memory
536220		akhan42	Bootfall (IZhO17_bootfall)	C++17	100 / 100	598 ms	4188 KiB

bootfall

#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); }


int mod = 1000 * 1000 * 1000 + 7;
int total = 0;
vi pol2;


int add(int a, int b) {
	int res = (a + b) % mod;
	return res < 0 ? res + mod : res;
}


int ct[250001];
vii changes;


void divide(int d, int sh) {
	changes.clear();
	for(int i = total; i - d >= 0 && i - d + sh >= total / 2; i--) {
		if(pol2[i] != 0) {
			changes.eb(i - d, pol2[i - d]);
			pol2[i - d] = add(pol2[i - d], -pol2[i]);
			ct[i - d + sh] += 1;
		}
	}

	for(ii p: changes)
		pol2[p.F] = p.S;
}


void solve() {
	int n;
	cin >> n;
	vi arr(n);
	set<int> nums;
	forn(i, n) {
		cin >> arr[i];
		nums.insert(arr[i]);
	}
	sort(all(arr));

	bool odd = true, even = true;
	for(int a: arr) {
		total += a;
		if(a % 2)
			even = false;
		else
			odd = false;
	}

	pol2.assign(total + 1, 0);
	pol2[0] = 1;
	for(int a: arr) {
		for(int i = total - a; i >= 0; i--) {
			pol2[i + a] = add(pol2[i + a], pol2[i]);
		}
	}



	if(total % 2 || pol2[total / 2] == 0 || (!even && !odd))
	{
		cout << 0;
		return;
	}


	int tt = sz(nums);

	for(int a: nums) {
		int d = (a + (odd ? 1 : 0)) / 2;
		divide(a, d);
	}

	vi vans;
	int rem = (odd ? 1 : 0) + total;
	forbn(i, (rem + 1) / 2, total + 1) {
		if(ct[i] == tt) {
			vans.pb(2 * i - rem);
		}
	}

	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();
	}
}

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