Submission #1022391

#	Time	Username	Problem	Language	Result	Execution time	Memory
1022391		phoenix	Bootfall (IZhO17_bootfall)	C++17	44 / 100	877 ms	3308 KiB

bootfall

#include <bits/stdc++.h>
 
using namespace std;
 
const int MOD1 = 1e9 + 7;
const int MOD2 = 998244353;
const int MOD3 = 999990011;
const int MOD4 = 1e9 + 9;
 
template<unsigned int MOD> 
struct mint {
    int v;
    mint() {}
    mint(long long val) : v(val - (val >= MOD) * MOD + (val < 0) * MOD) {}
    mint<MOD>& operator += (mint<MOD> other) {
        *this = mint(v + other.v);
        return *this;
    }
    mint<MOD>& operator -= (mint<MOD> other) {
        *this = mint(v - other.v);
        return *this;
    }
};
const int N = 550;
const int A = 250000;
 
mint<MOD1> dp1[A]{1};
mint<MOD2> dp2[A]{1};
// mint<MOD3> dp3[A]{1};
// mint<MOD4> dp4[A]{1};
int sum = 0;
 
void add(int val) {
    sum += val;
    for (int i = A - 1; i >= val; i--) {
        dp1[i] += dp1[i - val];
        dp2[i] += dp2[i - val];
        // dp3[i] += dp3[i - val];
        // dp4[i] += dp4[i - val];
    }   
}
 
bool check(int sum) {
    assert(0 <= sum && sum < A);
    bool flag = true;
    flag &= (dp1[sum].v > 0);
    flag &= (dp2[sum].v > 0);
    // flag &= (dp3[sum].v > 0);
    // flag &= (dp4[sum].v > 0);
    return flag;
}
 
void del(int val) {
    sum -= val;
    for (int i = val; i < A; i++) {
        dp1[i] -= dp1[i - val];
        dp2[i] -= dp2[i - val];
        // dp3[i] -= dp3[i - val];
        // dp4[i] -= dp4[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];
    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 < A; s++) {
            if (check(s)) {
                cnt[abs(2 * s - sum)]++;
            }
        }
    }
    vector<int> res;
    for (int i = 0; i < A; 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: 0 / 21
• Subtask 6: 0 / 35