Submission #1022428

#	Time	Username	Problem	Language	Result	Execution time	Memory
1022428		phoenix	Bootfall (IZhO17_bootfall)	C++17	100 / 100	270 ms	3560 KiB

bootfall

#include <bits/stdc++.h>
 
using namespace std;
 
const int N = 550;
const int A = 250250;
 
int lim = 0;
unsigned int dp[A]{1};

int sum = 0;
 
void add(int val) {
    sum += val;
    for (int i = lim; i >= val; i--) {
        dp[i] += dp[i - val];
    }   
}
 
bool check(int sum) {
    if (sum < 0 && sum > lim) return 0;
    return (dp[sum]);
}
 
void del(int val) {
    sum -= val;
    for (int i = val; i <= lim; i++) {
        dp[i] -= dp[i - val];
    }
}
 
int n;
int a[N];
int cnt[A];
 
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        lim += a[i];
    }
    for (int i = 0; i < n; i++) {
        add(a[i]);
    }
    if (sum & 1 || !check(sum / 2)) {
        cout << 0;
        return 0;
    }
 
    for (int i = 0; i < n; i++) {
        if (i) add(a[i - 1]);
        del(a[i]);
        for (int s = 0; s <= lim; s++) {
            if (check(s)) {
                cnt[abs(2 * s - sum)]++;
            }
        }
    }
    vector<int> res;
    for (int i = 1; i <= lim; i++) {
        if (cnt[i] == 2 * n) 
            res.push_back(i);
    }
    cout << (int)res.size() << '\n';
    for (int c : res) cout << c << ' ';
}

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