Submission #1104716

#	Time	Username	Problem	Language	Result	Execution time	Memory
1104716		SulA	XOR Sum (info1cup17_xorsum)	C++17	18 / 100	303 ms	592 KiB

xorsum

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);

    int n; cin >> n;
    if (n < 5000) {
        int a[n]; for (int i = 0; i < n; cin >> a[i++]);
        int ans = 0;
        for (int i = 0; i < n; i++) {
            for (int j = i; j < n; j++) {
                ans ^= a[i] + a[j];
            }
        }
        cout << ans;
        return 0;
    }
    const int K = 5000;
    bitset<2*K> el, pairs;

    for (int i = 0; i < n; i++) {
        int x; cin >> x;
        el.flip(x);
        pairs ^= el << x;
    }
    int ans = 0;
    for (int i = 0; i < 2*K; i++) {
        ans ^= (pairs[i])*i;
    }
    cout << ans;
}

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 38
• Subtask 5: 0 / 23