Submission #999498

#	Time	Username	Problem	Language	Result	Execution time	Memory
999498		LOLOLO	XOR Sum (info1cup17_xorsum)	C++17	45 / 100	1622 ms	9672 KiB

xorsum

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
 
#define           f     first
#define           s     second
#define           pb    push_back
#define           ep    emplace
#define           eb    emplace_back
#define           lb    lower_bound
#define           ub    upper_bound
#define       all(x)    x.begin(), x.end()
#define      rall(x)    x.rbegin(), x.rend()
#define   uniquev(v)    sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define     mem(f,x)    memset(f , x , sizeof(f))
#define        sz(x)    (ll)(x).size()
#define  __lcm(a, b)    (1ll * ((a) / __gcd((a), (b))) * (b))
#define          mxx    *max_element
#define          mnn    *min_element
#define    cntbit(x)    __builtin_popcountll(x)
#define       len(x)    (int)(x.length())
 
const int N = 1e6 + 10;
int a[N], n;
vector <int> v;

ll cal(int t) {
    ll ans = 0;
    for (int i = 0; i < sz(v); i++) {
        int p = lower_bound(all(v), t - v[i]) - v.begin();
        ans += max(0, i - p + 1);
    }

    return ans;
}

int is(int j) {
    ll t = cal((1 << (j + 1)) | ((1 << j))) + cal((1 << (j + 1))) - cal(1 << j);
    return t % 2;
}

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

    cin >> n;

    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }

    int ans = 0;
    for (int j = 0; j < 30; j++) {
        v.clear();
        for (int i = 1; i <= n; i++) {
            v.pb(a[i] % (1 << ((j + 1))));
        }

        sort(all(v));
        if (is(j))
            ans |= (1 << j);
    }

    cout << ans << '\n';
    return 0;
}
/*
011
011
*/

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