Submission #1201797

#	Time	Username	Problem	Language	Result	Execution time	Memory
1201797		M_SH_O	XOR Sum (info1cup17_xorsum)	C++20	77 / 100	1674 ms	25664 KiB

xorsum

#include <bits/stdc++.h>
/*#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>*/

#define ll long long
#define ll1 long long
#define ull unsigned long long
#define dou long double
#define str string
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vbool vector<bool>
#define vstr vector<str>
#define vvll vector<vll>
#define pb push_back
#define pf push_front
#define endl "\n"
#define fr first
#define se second
// #define sortcmp(a) sort(a.begin(), a.end(), cmp)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define speed ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define INF 5000000000000000000
#define ordered_set tree<ll, null_type, less_equal<ll>, rb_tree_tag, tree_order_statistics_node_update>

using namespace std;
//using namespace __gnu_pbds;

mt19937 rng(time(0));
ll randll(ll l, ll r){
    return uniform_int_distribution<ll>(l, r)(rng);
}

int main() {
    ll n;
    cin >> n;

    vll a(n);
    for (int i = 0; i < n; i ++) {
        cin >> a[i];
    }
    sort(a);
    ll res = 0;

    for (int i = 0; i < 29; i ++) {
        vll b, b1;
        ll k = 0;
        for (int j = 0; j < n; j ++) {
            if (a[j] & (1 << i)) b1.pb(a[j] & ((1 << i)-1));
            else b.pb(a[j] & ((1 << i)-1));
        }
        sort(b);
        sort(b1);

        ll l = b.size()-1, l1 = b1.size()-1;
        for (int j = 0; j < b.size(); j ++) {
            if ((b[j]+b[j]) >= (1 << i)) k ++;
            while (l >= 0) {
                if (b[l]+b[j] >= (1 << i)) l --;
                else break;
            }
            while (l1 >= 0) {
                if (b1[l1]+b[j] >= (1 << i)) l1 --;
                else break;
            }
            k += b.size()-l-1 + l1+1;
        }

        l = b.size()-1, l1 = b1.size()-1;
        for (int j = 0; j < b1.size(); j ++) {
            if ((b1[j]+b1[j]) >= (1 << i)) k ++;
            while (l >= 0) {
                if (b[l]+b1[j] >= (1 << i)) l --;
                else break;
            }
            while (l1 >= 0) {
                if (b1[l1]+b1[j] >= (1 << i)) l1 --;
                else break;
            }
            k += b1.size()-l1-1 + l+1;
        }
        //cout << k << endl;
        //if (i != 1) continue;

        /*for (int j : b) {
            cout << j << ' ';
        }
        cout << endl;
        for (int j : b1) {
            cout << j << ' ';
        }
        cout << endl;*/

        if (k/2 % 2) res += (1 << i);
    }

    cout << res << endl;
}

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