Submission #854064

#	Time	Username	Problem	Language	Result	Execution time	Memory
854064		The_Samurai	Bootfall (IZhO17_bootfall)	C++17	100 / 100	241 ms	17616 KiB

bootfall

#include "bits/stdc++.h"
using namespace std;
using ll = long long;
const ll inf = 1e18;
const int N = 250001, sq = 23;

int main() {
    cin.tie(0)->sync_with_stdio(false);
#ifdef sunnatov
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int n, sum = 0;
    cin >> n;
    vector<int> a(n);
    for (int &x: a) cin >> x;
    vector<bitset<N>> without(sq);
    bitset<N> bs; bs.set(0);
    for (int x: a) bs |= bs << x;
    for (int i = 0; i < sq; i++) {
        without[i].set(0);
        for (int j = 0; j < n; j++) {
            if (i * sq <= j and j < (i + 1) * sq) continue;
            without[i] |= without[i] << a[j];
        }
    }
    vector<bitset<N>> without_2(n);
    for (int i = 0; i < n; i++) {
        sum += a[i];
        without_2[i] = without[i / sq];
        for (int j = i - i % sq; j < min(n, i - i % sq + sq); j++) {
            if (i == j) continue;
            without_2[i] |= without_2[i] << a[j];
        }
    }
    vector<int> ans;
    for (int i = 1; i < N; i++) {
        if (sum % 2 or !bs[sum / 2]) continue;
        sum += i;
        bool ok = true;
        for (int j = 0; j < n and ok; j++) {
            sum -= a[j];
            if (sum % 2 or !without_2[j][sum / 2]) ok = false;
            sum += a[j];
        }
        sum -= i;
        if (ok) ans.emplace_back(i);
    }
    cout << ans.size() << '\n';
    for (int x: ans) cout << x << ' ';
}

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