Submission #496737

#	Time	Username	Problem	Language	Result	Execution time	Memory
496737		ergagan	XOR Sum (info1cup17_xorsum)	C++17	18 / 100	101 ms	8232 KiB

xorsum

//я так много думал, что опять попал
#include <bits/stdc++.h>
#define all(x) x.begin(),x.end()
#define pb push_back
#define ppb pop_back
#define pf push_front
#define ppf pop_front
#define f first
#define s second
#define left(v) v + v
#define right(v) v + v + 1
#define ub upper_bound
#define lb lower_bound

using namespace std;
typedef long long ll;

//17 SEVENTEEN
const long double Pi = acos(-1.0);
const ll dx[] = {0,0,1,-1};
const ll dy[] = {1,-1,0,0};
const ll N = (ll) 1e6 + 17;
const ll M = (ll) 5e3 + 69;
const ll inf = (ll) 1e14 + 3;
const ll mod = (ll) 1e9 + 7;
ll sq(ll x) { return x * x; }

ll zxc = 1, a[N], cnt[N];

void solve() {
    ll n, xr = 0;
    cin >> n;
    for(ll i = 1; i <= n; i++) {
        cin >> a[i];
        if(a[i] <= M) cnt[a[i]]++;
    }
    if(n <= M) {
        for(ll i = 1; i <= n; i++) {
            for(ll j = i; j <= n; j++) {
                xr ^= (a[i] + a[j]);
            }
        }
        cout << xr;
        return;
    }
    for(ll i = 1; i <= M; i++) {
        for(ll j = i; j <= M; j++) {
            if(cnt[i] && cnt[j]) {
                if(i == j && (cnt[i] * (cnt[i] + 1) / 2) % 2) xr ^= (i + j);
                if(cnt[i] * cnt[j] % 2 && i != j) xr ^= (i + j);
            }
        }
    }
    cout << xr;
}

int main(/*Уверенно*/) {
ios_base::sync_with_stdio(0);
    cin.tie(0);
/*
	freopen(".in", "r", stdin);
	freopen(".out", "w", stdout);
*/
//    cin >> zxc;
    while(zxc--) {
        solve();
    }
  	return 0;
}
// さよならさ いかなくちゃ

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