Submission #319238

#	Time	Username	Problem	Language	Result	Execution time	Memory
319238		BeanZ	Bootfall (IZhO17_bootfall)	C++14	100 / 100	212 ms	3300 KiB

bootfall

// I_Love_LPL
#include <bits/stdc++.h>
using namespace std;
#define task "A"
#define ll int
#define endl '\n'
const int N = 505;
const int mod = 1e9 + 7;
ll a[N];
bool chk[505];
const int lim = 500 * 500 + 5;
const int lim2 = 500 * 500 / 2 + 1;
bitset<lim> bit2, tmp;
ll sum = 0;
void solve(ll l, ll r, bitset<lim> bit){
    if (l == r){
        tmp.reset();
        for (int j = 0; j <= lim; j++){
            if ((sum - j - a[l] - j) <= 0) break;
            if (bit[j] && ((sum - j - a[l] - j) > 0)){
                tmp[sum - j - a[l] - j] = 1;
            }
        }
        bit2 = bit2 & tmp;
        return;
    }
    ll mid = (l + r) >> 1;
    bitset<lim> L, R;
    L = bit;
    R = bit;
    for (int i = mid + 1; i <= r; i++) R |= (R << a[i]);
    for (int i = l; i <= mid; i++) L |= (L << a[i]);
    solve(l, mid, R);
    solve(mid + 1, r, L);
}
bitset<lim> bit;
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    if (fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    ll n;
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i], sum += a[i];
    bit[0] = 1;
    for (int i = 1; i <= n; i++){
        bit |= (bit << a[i]);
    }
    if (bit[sum / 2] == 0) return cout << 0, 0;
    for (int i = 1; i < lim; i++) bit2[i] = 1;
    bit.reset();
    bit[0] = 1;
    solve(1, n, bit);
    vector<ll> ans;
    for (int i = 1; i < lim; i++){
        if (bit2[i]) ans.push_back(i);
    }
    cout << ans.size() << endl;
    for (auto j : ans) cout << j << " ";
}
/*
4
1 3 1 5
6
3 5 7 11 9 13
3
2 2 2
*/

Compilation message (stderr)

bootfall.cpp: In function 'int main()':
bootfall.cpp:41:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   41 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bootfall.cpp:42:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   42 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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