제출 #884238

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
884238		aykhn	XOR Sum (info1cup17_xorsum)	C++17	100 / 100	1024 ms	39784 KiB

xorsum

#include <bits/stdc++.h>
 
// author : aykhn
 
using namespace std;
typedef long long ll;
 
#define pb push_back
#define ins insert
#define mpr make_pair
#define all(v) v.begin(), v.end()
#define bpc __builtin_popcountll
#define pii pair<ll, ll>
#define pll pair<ll, ll>
#define fi first
#define se second
#define int ll
#define infll 0x3F3F3F3F3F3F3F3F
#define inf 0x3F3F3F3F

const int MXN = 1e5 + 5;

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(nullptr);
    int n;
    cin >> n;
    int a[n];
    pii b[n];
    for (int i = 0; i < n; i++) cin >> a[i], b[i] = mpr(0LL, i);
    int res = 0;
    for (int j = 0; j < 30; j++)
    {
        pii c[n];
        int l = 0;
        int r = n - 1;
        for (int i = n - 1; i >= 0; i--) if (a[b[i].se] >> j & 1) c[r--] = {b[i].fi | (1 << j), b[i].se};
        for (int i = 0; i < n; i++) if (!(a[b[i].se] >> j & 1)) c[l++] = b[i];
        for (int i = 0; i < n; i++) b[i] = c[i];
        int cnt = 0;
        int i1, i2, i3, i4;
        i1 = i2 = i3 = i4 = 0;
        for (int i = n - 1; i >= 0; i--)
        {
            while (i1 < n && b[i1].fi < (1 << j) - b[i].fi) i1++;
            while (i2 < n && b[i2].fi < (1 << (j + 1)) - b[i].fi) i2++;
            while (i3 < n && b[i3].fi < ((1 << (j + 1)) | (1 << j)) - b[i].fi) i3++;
            while (i4 < n && b[i4].fi < (1 << (j + 2)) - b[i].fi) i4++;
            if (max(i1, i) < i2) cnt += i2 - max(i1, i);
            if (max(i3, i) < i4) cnt += i4 - max(i3, i);
        }
        if (cnt & 1) res |= (1 << j);
    }
    cout << res << '\n';
}
// ignore (i + 1 -> 23];
// a[i] &= (1 << (i + 1)) - 1;
// (1 << i) <= a[i] + a[j] < (1 << (i + 1));
// (1 << (i + 1)) | (1 << i) <= a[i] + a[j] < (1 << (i + 2))

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