Submission #1009501

#	Time	Username	Problem	Language	Result	Execution time	Memory
1009501		windowwife	XOR Sum (info1cup17_xorsum)	C++17	11 / 100	364 ms	23676 KiB

xorsum

#include<bits/stdc++.h>
#define int unsigned
#define task " "
using namespace std;
const int maxn = 1e6 + 1, mod = 1e9 + 7;
int n, a[maxn], m[maxn], id[maxn], cnt = 0, idx = 0, res = 0, t, p, r;
vector<int> v[2];
signed main ()
{
    //freopen(task".INP", "r", stdin);
    //freopen(task".OUT", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
        m[i] = 0;
        id[i] = i;
    }
    m[n + 1] = (1U << 31);
    for (int j = 0; j <= 29; j++)
    {
        cnt = idx = 0; v[0].clear(); v[1].clear();
        for (int i = 1; i <= n; i++)
            v[(a[id[i]] >> j) & 1].push_back(id[i]);
        for (int i : v[0])
        {
            m[++idx] = a[i] & ((1U << (j + 1)) - 1);
            id[idx] = i;
        }
        for (int i : v[1])
        {
            m[++idx] = a[i] & ((1U << (j + 1)) - 1);
            id[idx] = i;
        }
        t = p = r = n + 1;
        for (int i = 1; i <= n; i++)
        {
            while (t > 1 && m[t - 1] >= (1U << (j + 1)) - m[i]) t--;
            while (p > 1 && m[p - 1] >= (1U << j) - m[i]) p--;
            while (r > 1 && m[r - 1] >= (1U << j) + (1U << (j + 1)) - m[i]) r--;
            cnt += (min(t, i + 1) - min(p, i + 1)) + (i + 1 - min(r, i + 1));
            //cnt += lower_bound(m + 1, m + i + 1, (1LL << (j + 1)) - m[i]) - lower_bound(m + 1, m + i + 1, (1LL << j) - m[i]);
            //cnt += lower_bound(m + 1, m + i + 1, (1LL << (j + 2)) - m[i]) - lower_bound(m + 1, m + i + 1, (1LL << j) + (1LL << (j + 1)) - m[i]);
        }
        res += (cnt & 1)*(1 << j);
    }
    cout << res;
}

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