Submission #644673

#	Time	Username	Problem	Language	Result	Execution time	Memory
644673		notme	XOR Sum (info1cup17_xorsum)	C++14	7 / 100	96 ms	8172 KiB

xorsum

#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
const int MAXN = 1e6 + 10;
void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

int n;
long long a[MAXN];
long long cnt[MAXN];
long long maxx = 0;
void read()
{
    cin >> n;
    for (int i = 1; i <= n; ++ i)
    {
        cin >> a[i];
        if(a[i] < 1e6 + 10)cnt[a[i]] ++;
        maxx = max(maxx, a[i]);
    }
}

void solve1()
{
    long long ans = 0;
    for (int i = 1; i <= n; ++ i)
    {
        for (int j = i; j <= n; ++ j)
        {
            ans = (ans ^ (a[i] + a[j]));
        }
    }
    cout << ans << endl;
}

void solve2()
{
    int ans = 0;
    for (int i = 1; i <= 4*1e3; ++ i)
    {
        for (int j = 1; j <= 4*1e3; ++ j)
        {
            int times = cnt[i] * cnt[j];
            int used = times / 2 + times % 2;
            if(used & 1)ans = (ans ^ (i + j));
        }
    }
    cout << ans << endl;
}
int main()
{
    speed();

    read();
    if(n <= 4 * 1e3)solve1();
    else if(maxx <= 4 * 1e3)solve2();
    return 0;
}

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