Submission #404382

#	Time	Username	Problem	Language	Result	Execution time	Memory
404382		fvogel499	Bootfall (IZhO17_bootfall)	C++14	100 / 100	634 ms	31772 KiB

bootfall

#include <iostream>
#include <bitset>

using namespace std;


const int siz = 250001;

int main() {
    cin.tie(0);
    ios_base::sync_with_stdio(0);

    int n;
    cin >> n;

    int raw [n];
    for (int i = 0; i < n; i++) cin >> raw[i];

    bitset<siz> check(0);
    check[0] = 1;
    int checkSum = 0;
    for (int i = 0; i < n; i++) {
        check |= check<<raw[i];
        checkSum += raw[i];
    }
    if (checkSum%2 == 1 or check[checkSum/2] == 0) {
        cout << 0;
        return 0;
    }

    bitset<siz> startToEnd [n];
    startToEnd[0] = bitset<siz>(0);
    startToEnd[0][0] = 1;
    for (int i = 1; i < n; i++) {
        startToEnd[i] = startToEnd[i-1]|(startToEnd[i-1]<<raw[i-1]);
    }

    bitset<siz> endToStart [n];
    endToStart[n-1] = bitset<siz>(0);
    endToStart[n-1][0] = 1;
    for (int i = n-2; i >= 0; i--) {
        endToStart[i] = endToStart[i+1]|(endToStart[i+1]<<raw[i+1]);
    }

    bitset<siz> even;
    bitset<siz> uneven;
    even.set();
    uneven.set();
    even[0] = 0;
    bool evenKilled = false;
    bool unevenKilled = false;
    bitset<siz> cur;
    int locSum;
    for (int i = 0; i < n; i++) {
        if (i > n/2) {
            cur = startToEnd[i];
            for (int j = i+1; j < n; j++) cur |= cur<<raw[j];
        }
        else {
            cur = endToStart[i];
            for (int j = i-1; j >= 0; j--) cur |= cur<<raw[j];
        }
        locSum = checkSum-raw[i];
        if (locSum%2 == 0) {
            even &= cur>>(locSum/2);
            if (!unevenKilled) {
                uneven &= 0;
                unevenKilled = true;
            }
        }
        else {
            uneven &= cur>>(locSum/2+1);
            if (!evenKilled) {
                even &= 0;
                evenKilled = true;
            }
        }
    }

    cout << even.count()+uneven.count() << endl;
    for (int i = 0; i < siz; i++) {
        if (even[i]) cout << i*2 << " ";
        if (uneven[i]) cout << i*2+1 << " ";
    }
}

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